pre-condition in code , fuzz and other misc updates (#4966)

* fuzz: rename 'filters' -> 'pre-condition'

* code proto: pre-condition + integration test

* feat: dsl document generator

* update dsl page header

* fix lint error

* add js defined helper funcs in docs

* remove panic recovery unless its for third party(go-rod,goja)

* handle dynamic values flattening edgecase in flow+multiprotocol

* fix order of kv in form-data (failing test)

* fix template loading counters

* Revert "handle dynamic values flattening edgecase in flow+multiprotocol"

This reverts commit 58fdd4faf7df5d654b46a9585011f614d5c98aa4.

* fix flow iteration using 'iterate'

.gitignore

@@ -35,4 +35,6 @@ pkg/protocols/headless/engine/.cache
 **/*-cache
 /fuzzplayground
 integration_tests/fuzzplayground
+/dsl.md
+
 

Makefile

@@ -47,4 +47,7 @@ fuzzplayground:
 memogen:
 	$(GOBUILD) $(GOFLAGS) -ldflags '$(LDFLAGS)' -o "memogen" cmd/memogen/memogen.go
 	./memogen -src pkg/js/libs -tpl cmd/memogen/function.tpl
-
+dsl-docs:
+	rm -f dsl.md scrapefuncs 2>/dev/null
+	$(GOBUILD) $(GOFLAGS) -ldflags '$(LDFLAGS)' -o "scrapefuncs" pkg/js/devtools/scrapefuncs/main.go
+	./scrapefuncs -out dsl.md

cmd/integration-test/code.go

@@ -23,6 +23,7 @@ var codeTestCases = []TestCaseInfo{
 	{Path: "protocols/code/py-nosig.yaml", TestCase: &codePyNoSig{}, DisableOn: isCodeDisabled},
 	{Path: "protocols/code/py-interactsh.yaml", TestCase: &codeSnippet{}, DisableOn: isCodeDisabled},
 	{Path: "protocols/code/ps1-snippet.yaml", TestCase: &codeSnippet{}, DisableOn: func() bool { return !osutils.IsWindows() || isCodeDisabled() }},
+	{Path: "protocols/code/pre-condition.yaml", TestCase: &codePreCondition{}, DisableOn: isCodeDisabled},
 }
 
 const (
@@ -94,6 +95,22 @@ func (h *codeSnippet) Execute(filePath string) error {
 	return expectResultsCount(results, 1)
 }
 
+type codePreCondition struct{}
+
+// Execute executes a test case and returns an error if occurred
+func (h *codePreCondition) Execute(filePath string) error {
+	results, err := testutils.RunNucleiArgsWithEnvAndGetResults(debug, getEnvValues(), "-t", filePath, "-u", "input", "-code")
+	if err != nil {
+		return err
+	}
+	if osutils.IsLinux() {
+		return expectResultsCount(results, 1)
+	} else {
+		return expectResultsCount(results, 0)
+
+	}
+}
+
 type codeFile struct{}
 
 // Execute executes a test case and returns an error if occurred

go.mod

@@ -97,7 +97,6 @@ require (
 	github.com/projectdiscovery/utils v0.0.85
 	github.com/projectdiscovery/wappalyzergo v0.0.112
 	github.com/redis/go-redis/v9 v9.1.0
-	github.com/sashabaranov/go-openai v1.15.3
 	github.com/seh-msft/burpxml v1.0.1
 	github.com/stretchr/testify v1.9.0
 	github.com/zmap/zgrab2 v0.1.8-0.20230806160807-97ba87c0e706
@@ -205,6 +204,7 @@ require (
 	github.com/projectdiscovery/stringsutil v0.0.2 // indirect
 	github.com/quic-go/quic-go v0.40.1 // indirect
 	github.com/refraction-networking/utls v1.6.1 // indirect
+	github.com/sashabaranov/go-openai v1.15.3 // indirect
 	github.com/shirou/gopsutil v3.21.11+incompatible // indirect
 	github.com/shoenig/go-m1cpu v0.1.6 // indirect
 	github.com/sirupsen/logrus v1.9.3 // indirect

integration_tests/flow/iterate-one-value-flow.yaml

@@ -4,10 +4,13 @@ info:
   name: Test Flow Iterate One Value Flow
   author: pdteam
   severity: info
+  description: |
+    If length of template.extracted variable is not know, i.e it could be an array of 1 or more values, then iterate function 
+    should be used to iterate over values because nuclei by default converts array to string if it has only 1 value.
 
 flow: |
   http(1)
-  for(let value of template.extracted){
+  for(let value of iterate(template.extracted)){
     set("value", value)
     http(2)
   }

integration_tests/fuzz/fuzz-body-generic-sqli.yaml

@@ -10,7 +10,7 @@ info:
     and performs fuzzing on the value of every key
 
 http:
-  - filters:
+  - pre-condition:
       - type: dsl
         dsl:
           - method != "GET"

integration_tests/fuzz/fuzz-body-json-sqli.yaml

@@ -10,7 +10,7 @@ info:
     Note: this is example template, and payloads/matchers need to be modified appropriately.
 
 http:
-  - filters:
+  - pre-condition:
       - type: dsl
         dsl:
           - method != "GET"

integration_tests/fuzz/fuzz-body-multipart-form-sqli.yaml

@@ -10,7 +10,7 @@ info:
     Note: this is example template, and payloads/matchers need to be modified appropriately.
 
 http:
-  - filters:
+  - pre-condition:
       - type: dsl
         dsl:
           - method != "GET"

integration_tests/fuzz/fuzz-body-params-sqli.yaml

@@ -10,7 +10,7 @@ info:
     Note: this is example template, and payloads/matchers need to be modified appropriately.
 
 http:
-  - filters:
+  - pre-condition:
       - type: dsl
         dsl:
           - method != "GET"

integration_tests/fuzz/fuzz-body-xml-sqli.yaml

@@ -10,7 +10,7 @@ info:
     Note: this is example template, and payloads/matchers need to be modified appropriately.
 
 http:
-  - filters:
+  - pre-condition:
       - type: dsl
         dsl:
           - method != "GET"

integration_tests/fuzz/fuzz-cookie-error-sqli.yaml

@@ -9,7 +9,7 @@ info:
     Note: this is example template, and payloads/matchers need to be modified appropriately.
 
 http:
-  - filters:
+  - pre-condition:
       - type: dsl
         dsl:
           - 'method == "GET"'

integration_tests/fuzz/fuzz-host-header-injection.yaml

@@ -10,7 +10,7 @@ variables:
   domain: "oast.fun"
 
 http:
-  - filters:
+  - pre-condition:
       - type: dsl
         dsl:
           - 'method == "GET"'

integration_tests/fuzz/fuzz-path-sqli.yaml

@@ -11,7 +11,7 @@ info:
     Note: this is example template, and payloads/matchers need to be modified appropriately.
 
 http:
-  - filters:
+  - pre-condition:
       - type: dsl
         dsl:
           - 'method == "GET"'

integration_tests/fuzz/fuzz-query-num-replace.yaml

@@ -7,7 +7,7 @@ info:
   description: Query Value Fuzzing using Fuzzing Rules
 
 http:
-  - filters:
+  - pre-condition:
       - type: dsl
         dsl:
           - 'len(query) > 0'
@@ -16,7 +16,7 @@ http:
         part: path
         words:
           - /blog/post
-    filters-condition: and
+    pre-condition-operator: and
 
     payloads:
       nums:

integration_tests/protocols/code/pre-condition.yaml

@@ -0,0 +1,26 @@
+id: pre-condition-code
+
+info:
+  name: example code template
+  author: pdteam
+  severity: info
+
+
+self-contained: true
+
+variables:
+  OAST: "{{interactsh-url}}"
+
+code:
+  - pre-condition: IsLinux()
+    engine:
+      - sh
+      - bash
+    source: |
+      echo "$OAST" | base64
+    
+    matchers:
+      - type: dsl
+        dsl:
+          - true
+# digest: 4a0a00473045022100c7215ce9f11e6a51c193bb54643a05cdd1cde18a3abb6c9983c5c7524d3ff03002203d93581c81d3ad5db463570cbbd2bdee529328d32a5b00e037610c211e448cef:4a3eb6b4988d95847d4203be25ed1d46

internal/runner/runner.go

@@ -688,14 +688,9 @@ func (r *Runner) displayExecutionInfo(store *loader.Store) {
 		}
 		for k, v := range templates.SignatureStats {
 			value := v.Load()
-			if k == templates.Unsigned && value > 0 {
-				// adjust skipped unsigned templates via code or -dut flag
-				value = value - uint64(stats.GetValue(templates.SkippedUnsignedStats))
-				value = value - uint64(stats.GetValue(templates.ExcludedCodeTmplStats))
-			}
 			if value > 0 {
 				if k == templates.Unsigned && !r.options.Silent && !config.DefaultConfig.HideTemplateSigWarning {
-					gologger.Print().Msgf("[%v] Loading %d unsigned templates for scan. Use with caution.", aurora.BrightYellow("WRN"), value)
+					gologger.Print().Msgf("[%v] Executing %d unsigned templates for scan. Use with caution.", aurora.BrightYellow("WRN"), value)
 				} else {
 					gologger.Info().Msgf("Executing %d signed templates from %s", value, k)
 				}

pkg/catalog/loader/loader.go

@@ -13,7 +13,6 @@ import (
 	"github.com/projectdiscovery/gologger"
 	"github.com/projectdiscovery/nuclei/v3/pkg/catalog"
 	"github.com/projectdiscovery/nuclei/v3/pkg/catalog/config"
-	cfg "github.com/projectdiscovery/nuclei/v3/pkg/catalog/config"
 	"github.com/projectdiscovery/nuclei/v3/pkg/catalog/loader/filter"
 	"github.com/projectdiscovery/nuclei/v3/pkg/model/types/severity"
 	"github.com/projectdiscovery/nuclei/v3/pkg/protocols"
@@ -387,6 +386,21 @@ func (store *Store) LoadTemplatesWithTags(templatesList, tags []string) []*templ
 	templatePathMap := store.pathFilter.Match(includedTemplates)
 
 	loadedTemplates := make([]*templates.Template, 0, len(templatePathMap))
+
+	loadTemplate := func(tmpl *templates.Template) {
+		loadedTemplates = append(loadedTemplates, tmpl)
+		// increment signed/unsigned counters
+		if tmpl.Verified {
+			if tmpl.TemplateVerifier == "" {
+				templates.SignatureStats[templates.PDVerifier].Add(1)
+			} else {
+				templates.SignatureStats[tmpl.TemplateVerifier].Add(1)
+			}
+		} else {
+			templates.SignatureStats[templates.Unsigned].Add(1)
+		}
+	}
+
 	for templatePath := range templatePathMap {
 		loaded, err := store.config.ExecutorOptions.Parser.LoadTemplate(templatePath, store.tagFilter, tags, store.config.Catalog)
 		if loaded || store.pathFilter.MatchIncluded(templatePath) {
@@ -412,7 +426,7 @@ func (store *Store) LoadTemplatesWithTags(templatesList, tags []string) []*templ
 				if store.config.ExecutorOptions.Options.DAST {
 					// check if the template is a DAST template
 					if parsed.IsFuzzing() {
-						loadedTemplates = append(loadedTemplates, parsed)
+						loadTemplate(parsed)
 					}
 				} else if len(parsed.RequestsHeadless) > 0 && !store.config.ExecutorOptions.Options.Headless {
 					// donot include headless template in final list if headless flag is not set
@@ -440,14 +454,14 @@ func (store *Store) LoadTemplatesWithTags(templatesList, tags []string) []*templ
 						gologger.Print().Msgf("[%v] -dast flag is required for DAST template '%s'.\n", aurora.Yellow("WRN").String(), templatePath)
 					}
 				} else {
-					loadedTemplates = append(loadedTemplates, parsed)
+					loadTemplate(parsed)
 				}
 			}
 		}
 		if err != nil {
 			if strings.Contains(err.Error(), templates.ErrExcluded.Error()) {
 				stats.Increment(templates.TemplatesExcludedStats)
-				if cfg.DefaultConfig.LogAllEvents {
+				if config.DefaultConfig.LogAllEvents {
 					gologger.Print().Msgf("[%v] %v\n", aurora.Yellow("WRN").String(), err.Error())
 				}
 				continue

pkg/fuzz/dataformat/form.go

@@ -2,7 +2,6 @@ package dataformat
 
 import (
 	"fmt"
-	"net/url"
 	"regexp"
 	"strconv"
 	"strings"
@@ -116,13 +115,11 @@ func (f *Form) Encode(data KV) (string, error) {
 
 // Decode decodes the data from Form format
 func (f *Form) Decode(data string) (KV, error) {
-	parsed, err := url.ParseQuery(data)
-	if err != nil {
-		return KV{}, err
-	}
+	ordered_params := urlutil.NewOrderedParams()
+	ordered_params.Merge(data)
 
 	values := mapsutil.NewOrderedMap[string, any]()
-	for key, value := range parsed {
+	ordered_params.Iterate(func(key string, value []string) bool {
 		if len(value) == 1 {
 			values.Set(key, value[0])
 		} else {
@@ -134,7 +131,8 @@ func (f *Form) Decode(data string) (KV, error) {
 			}
 			values.Set(key, value[len(value)-1])
 		}
-	}
+		return true
+	})
 	return KVOrderedMap(&values), nil
 }
 

pkg/fuzz/execute.go

@@ -64,11 +64,6 @@ type GeneratedRequest struct {
 // Input is not thread safe and should not be shared between concurrent
 // goroutines.
 func (rule *Rule) Execute(input *ExecuteRuleInput) (err error) {
-	defer func() {
-		if r := recover(); r != nil {
-			err = fmt.Errorf("got panic while executing rule: %v", r)
-		}
-	}()
 	if !rule.isInputURLValid(input.Input) {
 		return ErrRuleNotApplicable.Msgf("invalid input url: %v", input.Input.MetaInput.Input)
 	}

pkg/input/types/http.go

@@ -207,11 +207,6 @@ func (hr *HttpResponse) Clone() *HttpResponse {
 // and returns the request and response object
 // Note: it currently does not parse response and is meant to be added manually since its a optional field
 func ParseRawRequest(raw string) (rr *RequestResponse, err error) {
-	defer func() {
-		if r := recover(); r != nil {
-			err = fmt.Errorf("panic: %v", r)
-		}
-	}()
 	protoReader := textproto.NewReader(bufio.NewReader(strings.NewReader(raw)))
 	methodLine, err := protoReader.ReadLine()
 	if err != nil {

pkg/js/devtools/scrapefuncs/main.go

@@ -1,113 +1,92 @@
 package main
 
 import (
-	"bytes"
-	"context"
 	"flag"
 	"fmt"
 	"go/ast"
 	"go/parser"
 	"go/token"
-	"log"
 	"os"
+	"path/filepath"
+	"sort"
 	"strings"
 
-	filutil "github.com/projectdiscovery/utils/file"
-	"github.com/sashabaranov/go-openai"
+	mapsutil "github.com/projectdiscovery/utils/maps"
+	"golang.org/x/exp/maps"
 )
 
-var sysprompt = `
-data present after ---raw data--- contains raw data extracted by a parser and contains information about function 
---- example ---
-Name: log
-Signatures: "log(msg string)"
-Signatures: "log(msg map[string]interface{})"
-Description: log prints given input to stdout with [JS] prefix for debugging purposes 
---- end example ---
-Here Name is name of function , signature[s] is actual function declaration and description is description of function
-using this data for every such function generate a abstract implementation of function in javascript along with jsdoc annotations
---- example expected output---
-/**
- * log prints given input to stdout with [JS] prefix for debugging purposes
- * log(msg string)
- * log(msg map[string]interface{})
- * @function
- * @param {string} msg - The message to print.
- */
-function log(msg) {
-    // implemented in go
-};
---- instructions ---
-ACT as helpful coding assistant and do the same for all functions present in data
-`
-
-const userPrompt = `
----raw data---
-{{source}}
----new javascript---
-`
-
 var (
 	dir string
-	key     string
-	keyfile string
 	out string
 )
 
+type DSLHelperFunc struct {
+	Name        string
+	Description string
+	Signatures  []string
+}
+
+var pkg2NameMapping = map[string]string{
+	"code":       "Code Protocol",
+	"javascript": "JavaScript Protocol",
+	"global":     "Javascript Runtime",
+	"compiler":   "Javascript Runtime",
+	"flow":       "Template Flow",
+}
+
+var preferredOrder = []string{"Javascript Runtime", "Template Flow", "Code Protocol", "JavaScript Protocol"}
+
 func main() {
-	flag.StringVar(&dir, "dir", "pkg/js/global", "directory to process")
-	flag.StringVar(&key, "key", "", "openai api key")
-	flag.StringVar(&keyfile, "keyfile", "", "openai api key file")
-	flag.StringVar(&out, "out", "", "output js file with declarations of all global functions")
+	flag.StringVar(&dir, "dir", "pkg/", "directory to process")
+	flag.StringVar(&out, "out", "", "output markdown file with helper file declarations")
 	flag.Parse()
 
-	finalKey := ""
-	if key != "" {
-		key = finalKey
-	}
-	if keyfile != "" && filutil.FileExists(keyfile) {
-		data, err := os.ReadFile(keyfile)
-		if err != nil {
-			log.Fatal(err)
-		}
-		finalKey = string(data)
-	}
-	if key := os.Getenv("OPENAI_API_KEY"); key != "" {
-		finalKey = key
-	}
+	dirList := []string{}
 
-	if finalKey == "" {
-		log.Fatal("openai api key is not set")
+	if err := filepath.WalkDir(dir, func(path string, d os.DirEntry, err error) error {
+		if d.IsDir() {
+			dirList = append(dirList, path)
 		}
-	llm := openai.NewClient(finalKey)
-	var buff bytes.Buffer
+		return nil
+	}); err != nil {
+		panic(err)
+	}
+	pkgs := map[string]*ast.Package{}
 
+	for _, dir := range dirList {
 		fset := token.NewFileSet()
-	pkgs, err := parser.ParseDir(fset, dir, nil, 0)
+		pkgss, err := parser.ParseDir(fset, dir, nil, 0)
 		if err != nil {
 			fmt.Println(err)
 			return
 		}
+		pkgs = mapsutil.Merge(pkgs, pkgss)
+	}
+
+	dslHelpers := map[string][]DSLHelperFunc{}
 
 	for _, pkg := range pkgs {
-		for _, file := range pkg.Files {
+		for fname, file := range pkg.Files {
 			ast.Inspect(file, func(n ast.Node) bool {
 				switch x := n.(type) {
 				case *ast.CallExpr:
 					if sel, ok := x.Fun.(*ast.SelectorExpr); ok {
 						if sel.Sel.Name == "RegisterFuncWithSignature" {
+							hf := DSLHelperFunc{}
 							for _, arg := range x.Args {
 								if kv, ok := arg.(*ast.CompositeLit); ok {
 									for _, elt := range kv.Elts {
 										if kv, ok := elt.(*ast.KeyValueExpr); ok {
 											key := kv.Key.(*ast.Ident).Name
 											switch key {
-											case "Name", "Description":
-												buff.WriteString(fmt.Sprintf("%s: %s\n", key, strings.Trim(kv.Value.(*ast.BasicLit).Value, `"`)))
+											case "Name":
+												hf.Name = strings.Trim(kv.Value.(*ast.BasicLit).Value, `"`)
+											case "Description":
+												hf.Description = strings.Trim(kv.Value.(*ast.BasicLit).Value, `"`)
 											case "Signatures":
 												if comp, ok := kv.Value.(*ast.CompositeLit); ok {
 													for _, signature := range comp.Elts {
-														buff.WriteString(fmt.Sprintf("%s: %s\n", key, signature.(*ast.BasicLit).Value))
+														hf.Signatures = append(hf.Signatures, strings.Trim(signature.(*ast.BasicLit).Value, `"`))
 													}
 												}
 											}
@@ -115,7 +94,17 @@ func main() {
 									}
 								}
 							}
-							buff.WriteString("\n")
+							if hf.Name != "" {
+								identifier := pkg2NameMapping[pkg.Name]
+								if identifier == "" {
+									identifier = pkg.Name + "  (" + filepath.Dir(fname) + ")"
+								}
+
+								if dslHelpers[identifier] == nil {
+									dslHelpers[identifier] = []DSLHelperFunc{}
+								}
+								dslHelpers[identifier] = append(dslHelpers[identifier], hf)
+							}
 						}
 					}
 				}
@@ -124,32 +113,54 @@ func main() {
 		}
 	}
 
-	fmt.Printf("[+] Scraped %d functions\n\n", strings.Count(buff.String(), "Name:"))
-	fmt.Println(buff.String())
-
-	fmt.Printf("[+] Generating jsdoc for all functions\n\n")
-	resp, err := llm.CreateChatCompletion(context.TODO(), openai.ChatCompletionRequest{
-		Model: "gpt-4",
-		Messages: []openai.ChatCompletionMessage{
-			{Role: "system", Content: sysprompt},
-			{Role: "user", Content: strings.ReplaceAll(userPrompt, "{{source}}", buff.String())},
-		},
-		Temperature: 0.1,
-	})
-	if err != nil {
-		fmt.Println(err)
-		return
+	// DSL Helper functions stats
+	for pkg, funcs := range dslHelpers {
+		fmt.Printf("Found %d DSL Helper functions in package %s\n", len(funcs), pkg)
 	}
-	if len(resp.Choices) == 0 {
-		fmt.Println("no choices returned")
-		return
-	}
-	data := resp.Choices[0].Message.Content
-
-	fmt.Println(data)
 
+	// Generate Markdown tables with ## as package name
 	if out != "" {
-		if err := os.WriteFile(out, []byte(data), 0600); err != nil {
+		var sb strings.Builder
+		sb.WriteString(`---
+title: "Javascript Helper Functions"
+description: "Available JS Helper Functions that can be used in global js runtime & protocol specific helpers."
+icon: "function"
+iconType: "solid"
+---
+
+
+`)
+
+		actualKeys := maps.Keys(dslHelpers)
+		sort.Slice(actualKeys, func(i, j int) bool {
+			for _, preferredKey := range preferredOrder {
+				if actualKeys[i] == preferredKey {
+					return true
+				}
+				if actualKeys[j] == preferredKey {
+					return false
+				}
+			}
+			return actualKeys[i] < actualKeys[j]
+		})
+
+		for _, v := range actualKeys {
+			pkg := v
+			funcs := dslHelpers[pkg]
+			sb.WriteString("## " + pkg + "\n\n")
+			sb.WriteString("| Name | Description | Signatures |\n")
+			sb.WriteString("|------|-------------|------------|\n")
+			for _, f := range funcs {
+				sigSlice := []string{}
+				for _, sig := range f.Signatures {
+					sigSlice = append(sigSlice, "`"+sig+"`")
+				}
+				sb.WriteString(fmt.Sprintf("| %s | %s | %s |\n", f.Name, f.Description, strings.Join(sigSlice, ", ")))
+			}
+			sb.WriteString("\n")
+		}
+
+		if err := os.WriteFile(out, []byte(sb.String()), 0644); err != nil {
 			fmt.Println(err)
 			return
 		}

pkg/js/global/helpers.go

@@ -38,3 +38,40 @@ func registerAdditionalHelpers(runtime *goja.Runtime) {
 		},
 	})
 }
+
+func init() {
+	// these are dummy functions we use trigger documentation generation
+	// actual definations are in exports.js
+	_ = gojs.RegisterFuncWithSignature(nil, gojs.FuncOpts{
+		Name: "to_json",
+		Signatures: []string{
+			"to_json(any) object",
+		},
+		Description: "Converts a given object to JSON",
+	})
+
+	_ = gojs.RegisterFuncWithSignature(nil, gojs.FuncOpts{
+		Name: "dump_json",
+		Signatures: []string{
+			"dump_json(any)",
+		},
+		Description: "Prints a given object as JSON in console",
+	})
+
+	_ = gojs.RegisterFuncWithSignature(nil, gojs.FuncOpts{
+		Name: "to_array",
+		Signatures: []string{
+			"to_array(any) array",
+		},
+		Description: "Sets/Updates objects prototype to array to enable Array.XXX functions",
+	})
+
+	_ = gojs.RegisterFuncWithSignature(nil, gojs.FuncOpts{
+		Name: "hex_to_ascii",
+		Signatures: []string{
+			"hex_to_ascii(string) string",
+		},
+		Description: "Converts a given hex string to ascii",
+	})
+
+}

pkg/js/gojs/set.go

@@ -7,6 +7,7 @@ import (
 
 var (
 	ErrInvalidFuncOpts = errorutil.NewWithFmt("invalid function options: %v")
+	ErrNilRuntime      = errorutil.New("runtime is nil")
 )
 
 type FuncOpts struct {
@@ -23,6 +24,9 @@ func (f *FuncOpts) valid() bool {
 
 // RegisterFunc registers a function with given name, signatures and description
 func RegisterFuncWithSignature(runtime *goja.Runtime, opts FuncOpts) error {
+	if runtime == nil {
+		return ErrNilRuntime
+	}
 	if !opts.valid() {
 		return ErrInvalidFuncOpts.Msgf("name: %s, signatures: %v, description: %s", opts.Name, opts.Signatures, opts.Description)
 	}

pkg/protocols/code/code.go

@@ -8,11 +8,15 @@ import (
 	"strings"
 	"time"
 
+	"github.com/alecthomas/chroma/quick"
+	"github.com/ditashi/jsbeautifier-go/jsbeautifier"
+	"github.com/dop251/goja"
 	"github.com/pkg/errors"
 
 	"github.com/projectdiscovery/gologger"
 	"github.com/projectdiscovery/gozero"
 	gozerotypes "github.com/projectdiscovery/gozero/types"
+	"github.com/projectdiscovery/nuclei/v3/pkg/js/compiler"
 	"github.com/projectdiscovery/nuclei/v3/pkg/operators"
 	"github.com/projectdiscovery/nuclei/v3/pkg/operators/extractors"
 	"github.com/projectdiscovery/nuclei/v3/pkg/operators/matchers"
@@ -52,6 +56,9 @@ type Request struct {
 	//   Engine type
 	Engine []string `yaml:"engine,omitempty" jsonschema:"title=engine,description=Engine"`
 	// description: |
+	//   PreCondition is a condition which is evaluated before sending the request.
+	PreCondition string `yaml:"pre-condition,omitempty" json:"pre-condition,omitempty" jsonschema:"title=pre-condition for the request,description=PreCondition is a condition which is evaluated before sending the request"`
+	// description: |
 	//   Engine Arguments
 	Args []string `yaml:"args,omitempty" jsonschema:"title=args,description=Args"`
 	// description: |
@@ -61,9 +68,10 @@ type Request struct {
 	//   Source File/Snippet
 	Source string `yaml:"source,omitempty" jsonschema:"title=source file/snippet,description=Source snippet"`
 
-	options *protocols.ExecutorOptions
-	gozero  *gozero.Gozero
-	src     *gozero.Source
+	options              *protocols.ExecutorOptions `yaml:"-" json:"-"`
+	preConditionCompiled *goja.Program              `yaml:"-" json:"-"`
+	gozero               *gozero.Gozero             `yaml:"-" json:"-"`
+	src                  *gozero.Source             `yaml:"-" json:"-"`
 }
 
 // Compile compiles the request generators preparing any requests possible.
@@ -110,6 +118,15 @@ func (request *Request) Compile(options *protocols.ExecutorOptions) error {
 		}
 		request.CompiledOperators = compiled
 	}
+
+	// compile pre-condition if any
+	if request.PreCondition != "" {
+		preConditionCompiled, err := compiler.WrapScriptNCompile(request.PreCondition, false)
+		if err != nil {
+			return errorutil.NewWithTag(request.TemplateID, "could not compile pre-condition: %s", err)
+		}
+		request.preConditionCompiled = preConditionCompiled
+	}
 	return nil
 }
 
@@ -130,11 +147,6 @@ func (request *Request) ExecuteWithResults(input *contextargs.Context, dynamicVa
 		return err
 	}
 	defer func() {
-		// catch any panics just in case
-		if r := recover(); r != nil {
-			gologger.Error().Msgf("[%s] Panic occurred in code protocol: %s\n", request.options.TemplateID, r)
-			err = fmt.Errorf("panic occurred: %s", r)
-		}
 		if err := metaSrc.Cleanup(); err != nil {
 			gologger.Warning().Msgf("%s\n", err)
 		}
@@ -160,7 +172,45 @@ func (request *Request) ExecuteWithResults(input *contextargs.Context, dynamicVa
 		allvars[name] = v
 		metaSrc.AddVariable(gozerotypes.Variable{Name: name, Value: v})
 	}
+
+	// set timeout using multiplier
 	timeout := TimeoutMultiplier * request.options.Options.Timeout
+
+	if request.PreCondition != "" {
+		if request.options.Options.Debug || request.options.Options.DebugRequests {
+			gologger.Debug().Msgf("[%s] Executing Precondition for Code request\n", request.TemplateID)
+			var highlightFormatter = "terminal256"
+			if request.options.Options.NoColor {
+				highlightFormatter = "text"
+			}
+			var buff bytes.Buffer
+			_ = quick.Highlight(&buff, beautifyJavascript(request.PreCondition), "javascript", highlightFormatter, "monokai")
+			prettyPrint(request.TemplateID, buff.String())
+		}
+
+		args := compiler.NewExecuteArgs()
+		args.TemplateCtx = allvars
+
+		result, err := request.options.JsCompiler.ExecuteWithOptions(request.preConditionCompiled, args,
+			&compiler.ExecuteOptions{
+				Timeout:  timeout,
+				Source:   &request.PreCondition,
+				Callback: registerPreConditionFunctions,
+				Cleanup:  cleanUpPreConditionFunctions,
+			})
+		if err != nil {
+			return errorutil.NewWithTag(request.TemplateID, "could not execute pre-condition: %s", err)
+		}
+		if !result.GetSuccess() || types.ToString(result["error"]) != "" {
+			gologger.Warning().Msgf("[%s] Precondition for request %s was not satisfied\n", request.TemplateID, request.PreCondition)
+			request.options.Progress.IncrementFailedRequestsBy(1)
+			return nil
+		}
+		if request.options.Options.Debug || request.options.Options.DebugRequests {
+			gologger.Debug().Msgf("[%s] Precondition for request was satisfied\n", request.TemplateID)
+		}
+	}
+
 	ctx, cancel := context.WithTimeout(context.Background(), time.Duration(timeout)*time.Second)
 	defer cancel()
 	// Note: we use contextutil despite the fact that gozero accepts context as argument
@@ -336,3 +386,23 @@ func interpretEnvVars(source string, vars map[string]interface{}) string {
 	}
 	return source
 }
+
+func beautifyJavascript(code string) string {
+	opts := jsbeautifier.DefaultOptions()
+	beautified, err := jsbeautifier.Beautify(&code, opts)
+	if err != nil {
+		return code
+	}
+	return beautified
+}
+
+func prettyPrint(templateId string, buff string) {
+	lines := strings.Split(buff, "\n")
+	final := []string{}
+	for _, v := range lines {
+		if v != "" {
+			final = append(final, "\t"+v)
+		}
+	}
+	gologger.Debug().Msgf(" [%v] Pre-condition Code:\n\n%v\n\n", templateId, strings.Join(final, "\n"))
+}

pkg/protocols/code/helpers.go

@@ -0,0 +1,272 @@
+package code
+
+import (
+	goruntime "runtime"
+
+	"github.com/dop251/goja"
+	"github.com/projectdiscovery/nuclei/v3/pkg/js/gojs"
+	osutils "github.com/projectdiscovery/utils/os"
+)
+
+// registerPreConditionFunctions registers the pre-condition functions
+func registerPreConditionFunctions(runtime *goja.Runtime) error {
+	// Note: the only reason we are not using forloop to generate these functions is because
+	// 'scrapefuncs' uses this function to find all dsl helper functions  and document them.
+
+	// === OS ===
+	err := gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name: "OS",
+		Signatures: []string{
+			"OS() string",
+		},
+		Description: "OS returns the current OS",
+		FuncDecl: func() string {
+			return goruntime.GOOS
+		},
+	})
+	if err != nil {
+		return err
+	}
+
+	// IsLinux checks if the current OS is Linux
+	err = gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name: "IsLinux",
+		Signatures: []string{
+			"IsLinux() bool",
+		},
+		Description: "IsLinux checks if the current OS is Linux",
+		FuncDecl: func() bool {
+			return osutils.IsLinux()
+		},
+	})
+	if err != nil {
+		return err
+	}
+
+	// IsWindows checks if the current OS is Windows
+	err = gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name: "IsWindows",
+		Signatures: []string{
+			"IsWindows() bool",
+		},
+		Description: "IsWindows checks if the current OS is Windows",
+		FuncDecl: func() bool {
+			return osutils.IsWindows()
+		},
+	})
+	if err != nil {
+		return err
+	}
+
+	// IsOSX checks if the current OS is OSX
+	err = gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name: "IsOSX",
+		Signatures: []string{
+			"IsOSX() bool",
+		},
+		Description: "IsOSX checks if the current OS is OSX",
+
+		FuncDecl: func() bool {
+			return osutils.IsOSX()
+		},
+	})
+	if err != nil {
+		return err
+	}
+
+	// IsAndroid checks if the current OS is Android
+	err = gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name: "IsAndroid",
+		Signatures: []string{
+			"IsAndroid() bool",
+		},
+		Description: "IsAndroid checks if the current OS is Android",
+		FuncDecl: func() bool {
+			return osutils.IsAndroid()
+		},
+	})
+	if err != nil {
+		return err
+	}
+
+	// IsIOS checks if the current OS is IOS
+	err = gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name: "IsIOS",
+		Signatures: []string{
+			"IsIOS() bool",
+		},
+		Description: "IsIOS checks if the current OS is IOS",
+		FuncDecl: func() bool {
+			return osutils.IsIOS()
+		},
+	})
+	if err != nil {
+		return err
+	}
+
+	// IsJS checks if the current OS is JS
+	err = gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name: "IsJS",
+		Signatures: []string{
+			"IsJS() bool",
+		},
+		Description: "IsJS checks if the current OS is JS",
+		FuncDecl: func() bool {
+			return osutils.IsJS()
+		},
+	})
+	if err != nil {
+		return err
+	}
+
+	// IsFreeBSD checks if the current OS is FreeBSD
+	err = gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name: "IsFreeBSD",
+		Signatures: []string{
+			"IsFreeBSD() bool",
+		},
+		Description: "IsFreeBSD checks if the current OS is FreeBSD",
+		FuncDecl: func() bool {
+			return osutils.IsFreeBSD()
+		},
+	})
+	if err != nil {
+		return err
+	}
+
+	// IsOpenBSD checks if the current OS is OpenBSD
+	err = gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name: "IsOpenBSD",
+		Signatures: []string{
+			"IsOpenBSD() bool",
+		},
+		Description: "IsOpenBSD checks if the current OS is OpenBSD",
+		FuncDecl: func() bool {
+			return osutils.IsOpenBSD()
+		},
+	})
+	if err != nil {
+		return err
+	}
+
+	// IsSolaris checks if the current OS is Solaris
+	err = gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name: "IsSolaris",
+		Signatures: []string{
+			"IsSolaris() bool",
+		},
+		Description: "IsSolaris checks if the current OS is Solaris",
+		FuncDecl: func() bool {
+			return osutils.IsSolaris()
+		},
+	})
+	if err != nil {
+		return err
+	}
+
+	// === Arch ===
+	err = gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name: "Arch",
+		Signatures: []string{
+			"Arch() string",
+		},
+		Description: "Arch returns the current architecture",
+		FuncDecl: func() string {
+			return goruntime.GOARCH
+		},
+	})
+	if err != nil {
+		return err
+	}
+
+	err = gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name: "Is386",
+		Signatures: []string{
+			"Is386() bool",
+		},
+		Description: "Is386 checks if the current architecture is 386",
+		FuncDecl: func() bool {
+			return osutils.Is386()
+		},
+	})
+	if err != nil {
+		return err
+	}
+
+	err = gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name: "IsAmd64",
+		Signatures: []string{
+			"IsAmd64() bool",
+		},
+		Description: "IsAmd64 checks if the current architecture is Amd64",
+		FuncDecl: func() bool {
+			return osutils.IsAmd64()
+		},
+	})
+	if err != nil {
+		return err
+	}
+
+	err = gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name: "IsARM",
+		Signatures: []string{
+			"IsARM() bool",
+		},
+		Description: "IsArm checks if the current architecture is Arm",
+		FuncDecl: func() bool {
+			return osutils.IsARM()
+		},
+	})
+	if err != nil {
+		return err
+	}
+
+	err = gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name: "IsARM64",
+		Signatures: []string{
+			"IsARM64() bool",
+		},
+		Description: "IsArm64 checks if the current architecture is Arm64",
+		FuncDecl: func() bool {
+			return osutils.IsARM64()
+		},
+	})
+	if err != nil {
+		return err
+	}
+
+	err = gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name: "IsWasm",
+		Signatures: []string{
+			"IsWasm() bool",
+		},
+		Description: "IsWasm checks if the current architecture is Wasm",
+		FuncDecl: func() bool {
+			return osutils.IsWasm()
+		},
+	})
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func cleanUpPreConditionFunctions(runtime *goja.Runtime) {
+	_ = runtime.GlobalObject().Delete("OS")
+	_ = runtime.GlobalObject().Delete("IsLinux")
+	_ = runtime.GlobalObject().Delete("IsWindows")
+	_ = runtime.GlobalObject().Delete("IsOSX")
+	_ = runtime.GlobalObject().Delete("IsAndroid")
+	_ = runtime.GlobalObject().Delete("IsIOS")
+	_ = runtime.GlobalObject().Delete("IsJS")
+	_ = runtime.GlobalObject().Delete("IsFreeBSD")
+	_ = runtime.GlobalObject().Delete("IsOpenBSD")
+	_ = runtime.GlobalObject().Delete("IsSolaris")
+	_ = runtime.GlobalObject().Delete("Arch")
+	_ = runtime.GlobalObject().Delete("Is386")
+	_ = runtime.GlobalObject().Delete("IsAmd64")
+	_ = runtime.GlobalObject().Delete("IsARM")
+	_ = runtime.GlobalObject().Delete("IsARM64")
+	_ = runtime.GlobalObject().Delete("IsWasm")
+}

pkg/protocols/http/http.go

@@ -211,13 +211,12 @@ type Request struct {
 	//  DisablePathAutomerge disables merging target url path with raw request path
 	DisablePathAutomerge bool `yaml:"disable-path-automerge,omitempty" json:"disable-path-automerge,omitempty" jsonschema:"title=disable auto merging of path,description=Disable merging target url path with raw request path"`
 	// description: |
-	//   Filter is matcher-like field to check if fuzzing should be performed on this request or not
-	FuzzingFilter []*matchers.Matcher `yaml:"filters,omitempty" json:"filter,omitempty" jsonschema:"title=filter for fuzzing,description=Filter is matcher-like field to check if fuzzing should be performed on this request or not"`
+	//   Fuzz PreCondition is matcher-like field to check if fuzzing should be performed on this request or not
+	FuzzPreCondition []*matchers.Matcher `yaml:"pre-condition,omitempty" json:"pre-condition,omitempty" jsonschema:"title=pre-condition for fuzzing/dast,description=PreCondition is matcher-like field to check if fuzzing should be performed on this request or not"`
 	// description: |
-	//   Filter condition is the condition to apply on the filter (AND/OR). Default is OR
-	FuzzingFilterCondition string `yaml:"filters-condition,omitempty" json:"filter-condition,omitempty" jsonschema:"title=condition between the filters,description=Conditions between the filters,enum=and,enum=or"`
-	// cached variables that may be used along with request.
-	fuzzingFilterCondition matchers.ConditionType `yaml:"-" json:"-"`
+	//  FuzzPreConditionOperator is the operator between multiple PreConditions for fuzzing Default is OR
+	FuzzPreConditionOperator string                 `yaml:"pre-condition-operator,omitempty" json:"pre-condition-operator,omitempty" jsonschema:"title=condition between the filters,description=Operator to use between multiple per-conditions,enum=and,enum=or"`
+	fuzzPreConditionOperator matchers.ConditionType `yaml:"-" json:"-"`
 }
 
 // Options returns executer options for http request
@@ -326,13 +325,13 @@ func (request *Request) Compile(options *protocols.ExecutorOptions) error {
 
 	// === fuzzing filters ===== //
 
-	if request.FuzzingFilterCondition != "" {
-		request.fuzzingFilterCondition = matchers.ConditionTypes[request.FuzzingFilterCondition]
+	if request.FuzzPreConditionOperator != "" {
+		request.fuzzPreConditionOperator = matchers.ConditionTypes[request.FuzzPreConditionOperator]
 	} else {
-		request.fuzzingFilterCondition = matchers.ORCondition
+		request.fuzzPreConditionOperator = matchers.ORCondition
 	}
 
-	for _, filter := range request.FuzzingFilter {
+	for _, filter := range request.FuzzPreCondition {
 		if err := filter.CompileMatchers(); err != nil {
 			return errors.Wrap(err, "could not compile matcher")
 		}

pkg/protocols/http/request.go

@@ -137,11 +137,6 @@ func (request *Request) executeRaceRequest(input *contextargs.Context, previous
 		// execute http request
 		go func(httpRequest *generatedRequest) {
 			defer spmHandler.Release()
-			defer func() {
-				if r := recover(); r != nil {
-					gologger.Verbose().Msgf("[%s] Recovered from panic: %v\n", request.options.TemplateID, r)
-				}
-			}()
 			if spmHandler.FoundFirstMatch() {
 				// stop sending more requests condition is met
 				return
@@ -218,11 +213,6 @@ func (request *Request) executeParallelHTTP(input *contextargs.Context, dynamicV
 		spmHandler.Acquire()
 		go func(httpRequest *generatedRequest) {
 			defer spmHandler.Release()
-			defer func() {
-				if r := recover(); r != nil {
-					gologger.Verbose().Msgf("[%s] Recovered from panic: %v\n", request.options.TemplateID, r)
-				}
-			}()
 			if spmHandler.FoundFirstMatch() {
 				return
 			}
@@ -319,11 +309,6 @@ func (request *Request) executeTurboHTTP(input *contextargs.Context, dynamicValu
 		spmHandler.Acquire()
 		go func(httpRequest *generatedRequest) {
 			defer spmHandler.Release()
-			defer func() {
-				if r := recover(); r != nil {
-					gologger.Verbose().Msgf("[%s] Recovered from panic: %v\n", request.options.TemplateID, r)
-				}
-			}()
 			if spmHandler.FoundFirstMatch() {
 				// skip if first match is found
 				return

pkg/protocols/http/request_fuzz.go

@@ -194,11 +194,11 @@ func (request *Request) executeGeneratedFuzzingRequest(gr fuzz.GeneratedRequest,
 
 // ShouldFuzzTarget checks if given target should be fuzzed or not using `filter` field in template
 func (request *Request) ShouldFuzzTarget(input *contextargs.Context) bool {
-	if len(request.FuzzingFilter) == 0 {
+	if len(request.FuzzPreCondition) == 0 {
 		return true
 	}
 	status := []bool{}
-	for index, filter := range request.FuzzingFilter {
+	for index, filter := range request.FuzzPreCondition {
 		isMatch, _ := request.Match(request.filterDataMap(input), filter)
 		status = append(status, isMatch)
 		if request.options.Options.MatcherStatus {
@@ -209,7 +209,7 @@ func (request *Request) ShouldFuzzTarget(input *contextargs.Context) bool {
 		return true
 	}
 	var matched bool
-	if request.fuzzingFilterCondition == matchers.ANDCondition {
+	if request.fuzzPreConditionOperator == matchers.ANDCondition {
 		matched = operators.EvalBoolSlice(status, true)
 	} else {
 		matched = operators.EvalBoolSlice(status, false)

pkg/templates/compile.go

@@ -36,6 +36,7 @@ var (
 
 const (
 	Unsigned   = "unsigned"
+	PDVerifier = "projectdiscovery/nuclei-templates"
 )
 
 func init() {
@@ -272,7 +273,6 @@ func ParseTemplateFromReader(reader io.Reader, preprocessor Preprocessor, option
 			if config.DefaultConfig.LogAllEvents {
 				gologger.DefaultLogger.Print().Msgf("[%v] Template %s is not signed or tampered\n", aurora.Yellow("WRN").String(), template.ID)
 			}
-			SignatureStats[Unsigned].Add(1)
 		}
 		return template, nil
 	}
@@ -293,7 +293,6 @@ func ParseTemplateFromReader(reader io.Reader, preprocessor Preprocessor, option
 		if config.DefaultConfig.LogAllEvents {
 			gologger.DefaultLogger.Print().Msgf("[%v] Template %s is not signed or tampered\n", aurora.Yellow("WRN").String(), template.ID)
 		}
-		SignatureStats[Unsigned].Add(1)
 	}
 
 	generatedConstants := map[string]interface{}{}
@@ -399,7 +398,7 @@ func parseTemplate(data []byte, options protocols.ExecutorOptions) (*Template, e
 	for _, verifier = range signer.DefaultTemplateVerifiers {
 		template.Verified, _ = verifier.Verify(data, template)
 		if template.Verified {
-			SignatureStats[verifier.Identifier()].Add(1)
+			template.TemplateVerifier = verifier.Identifier()
 			break
 		}
 	}

pkg/templates/templates.go

@@ -154,7 +154,8 @@ type Template struct {
 
 	// Verified defines if the template signature is digitally verified
 	Verified bool `yaml:"-" json:"-"`
-
+	// TemplateVerifier is identifier verifier used to verify the template (default nuclei-templates have projectdiscovery/nuclei-templates)
+	TemplateVerifier string `yaml:"-" json:"-"`
 	// RequestsQueue contains all template requests in order (both protocol & request order)
 	RequestsQueue []protocols.Request `yaml:"-" json:"-"`
 

pkg/templates/workflows.go

@@ -101,6 +101,17 @@ func parseWorkflowTemplate(workflow *workflows.WorkflowTemplate, preprocessor Pr
 				continue
 			}
 		}
+
+		// increment signed/unsigned counters
+		if template.Verified {
+			if template.TemplateVerifier == "" {
+				SignatureStats[PDVerifier].Add(1)
+			} else {
+				SignatureStats[template.TemplateVerifier].Add(1)
+			}
+		} else {
+			SignatureStats[Unsigned].Add(1)
+		}
 		workflowTemplates = append(workflowTemplates, template)
 	}
 

pkg/tmplexec/exec.go

@@ -3,7 +3,6 @@ package tmplexec
 import (
 	"errors"
 	"fmt"
-	"runtime/debug"
 	"strings"
 	"sync/atomic"
 
@@ -99,14 +98,6 @@ func (e *TemplateExecuter) Execute(ctx *scan.ScanContext) (bool, error) {
 		// since it is of no use after scan is completed (regardless of success or failure)
 		e.options.RemoveTemplateCtx(ctx.Input.MetaInput)
 	}()
-	defer func() {
-		// try catching unknown panics
-		if r := recover(); r != nil {
-			stacktrace := debug.Stack()
-			ctx.LogError(fmt.Errorf("panic: %v\n%s", r, stacktrace))
-			gologger.Verbose().Msgf("panic: %v\n%s", r, stacktrace)
-		}
-	}()
 
 	var lastMatcherEvent *output.InternalWrappedEvent
 	writeFailureCallback := func(event *output.InternalWrappedEvent, matcherStatus bool) {

pkg/tmplexec/flow/flow_executor.go

@@ -8,7 +8,6 @@ import (
 	"sync/atomic"
 
 	"github.com/dop251/goja"
-	"github.com/projectdiscovery/gologger"
 	"github.com/projectdiscovery/nuclei/v3/pkg/protocols"
 	"github.com/projectdiscovery/nuclei/v3/pkg/protocols/common/generators"
 	"github.com/projectdiscovery/nuclei/v3/pkg/scan"
@@ -175,13 +174,6 @@ func (f *FlowExecutor) Compile() error {
 
 // ExecuteWithResults executes the flow and returns results
 func (f *FlowExecutor) ExecuteWithResults(ctx *scan.ScanContext) error {
-	defer func() {
-		if e := recover(); e != nil {
-			f.ctx.LogError(fmt.Errorf("panic occurred while executing target %v with flow: %v", ctx.Input.MetaInput.Input, e))
-			gologger.Error().Label(f.options.TemplateID).Msgf("panic occurred while executing target %v with flow: %v", ctx.Input.MetaInput.Input, e)
-		}
-	}()
-
 	f.ctx.Input = ctx.Input
 	// -----Load all types of variables-----
 	// add all input args to template context

pkg/tmplexec/flow/flow_internal.go

@@ -96,10 +96,12 @@ func (f *FlowExecutor) protocolResultCallback(req protocols.Request, matcherStat
 						if len(v) == 1 {
 							// add it to flatten keys list so it will be flattened to a string later
 							f.flattenKeys = append(f.flattenKeys, k)
-						}
-						// always preserve extracted value type
+							// flatten and convert it to string
+							f.options.GetTemplateCtx(f.ctx.Input.MetaInput).Set(k, v[0])
+						} else {
+							// keep it as slice
 							f.options.GetTemplateCtx(f.ctx.Input.MetaInput).Set(k, v)
-
+						}
 					}
 				}
 			} else if !result.HasOperatorResult() && !hasOperators(req.GetCompiledOperators()) {

pkg/tmplexec/flow/vm.go

@@ -7,6 +7,7 @@ import (
 	"github.com/dop251/goja"
 	"github.com/logrusorgru/aurora"
 	"github.com/projectdiscovery/gologger"
+	"github.com/projectdiscovery/nuclei/v3/pkg/js/gojs"
 	"github.com/projectdiscovery/nuclei/v3/pkg/protocols/common/protocolstate"
 	"github.com/projectdiscovery/nuclei/v3/pkg/protocols/common/utils/vardump"
 	"github.com/projectdiscovery/nuclei/v3/pkg/tmplexec/flow/builtin"
@@ -49,8 +50,14 @@ var gojapool = &sync.Pool{
 }
 
 func registerBuiltins(runtime *goja.Runtime) {
-	_ = runtime.Set("log", func(call goja.FunctionCall) goja.Value {
-		// TODO: verify string interpolation and handle multiple args
+
+	_ = gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name:        "log",
+		Description: "Logs a given object/message to stdout (only for debugging purposes)",
+		Signatures: []string{
+			"log(obj any) any",
+		},
+		FuncDecl: func(call goja.FunctionCall) goja.Value {
 			arg := call.Argument(0).Export()
 			switch value := arg.(type) {
 			case string:
@@ -61,9 +68,16 @@ func registerBuiltins(runtime *goja.Runtime) {
 				gologger.DefaultLogger.Print().Msgf("[%v] %v", aurora.BrightCyan("JS"), value)
 			}
 			return call.Argument(0) // return the same value
+		},
 	})
 
-	_ = runtime.Set("iterate", func(call goja.FunctionCall) goja.Value {
+	_ = gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name:        "iterate",
+		Description: "Normalizes and Iterates over all arguments (can be a string,array,null etc) and returns an array of objects\nNote: If the object type is unknown(i.e could be a string or array) iterate should be used and it will always return an array of strings",
+		Signatures: []string{
+			"iterate(...any) []any",
+		},
+		FuncDecl: func(call goja.FunctionCall) goja.Value {
 			allVars := []any{}
 			for _, v := range call.Arguments {
 				if v.Export() == nil {
@@ -81,14 +95,23 @@ func registerBuiltins(runtime *goja.Runtime) {
 				}
 			}
 			return runtime.ToValue(allVars)
+		},
 	})
 
-	_ = runtime.Set("Dedupe", func(call goja.ConstructorCall) *goja.Object {
+	_ = gojs.RegisterFuncWithSignature(runtime, gojs.FuncOpts{
+		Name:        "Dedupe",
+		Description: "De-duplicates given values and returns a new array of unique values",
+		Signatures: []string{
+			"new Dedupe()",
+		},
+		FuncDecl: func(call goja.ConstructorCall) *goja.Object {
 			d := builtin.NewDedupe(runtime)
 			obj := call.This
 			// register these methods
 			_ = obj.Set("Add", d.Add)
 			_ = obj.Set("Values", d.Values)
 			return nil
+		},
 	})
+
 }