Sigma Rule Library

Potential CVE-2021-27905 Exploitation Attempt

Detects exploitation attempt of the CVE-2021-27905 which affects all Apache Solr versions prior to and including 8.8.1.

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Detection logic

selection_request1

cs-uri-query|contains|all:
  - /solr/
  - /debug/dump?
  - param=ContentStream
sc-status: 200

selection_request2

cs-method: GET
cs-uri-query|contains|all:
  - /solr/
  - command=fetchindex
  - masterUrl=
sc-status: 200

Condition

1 of selection_*

Raw YAML

title: Potential CVE-2021-27905 Exploitation Attempt
id: 0bbcd74b-0596-41a4-94a0-4e88a76ffdb3
status: test
description: Detects exploitation attempt of the CVE-2021-27905 which affects all Apache Solr versions prior to and including 8.8.1.
references:
    - https://twitter.com/Al1ex4/status/1382981479727128580
    - https://twitter.com/sec715/status/1373472323538362371
    - https://nsfocusglobal.com/apache-solr-arbitrary-file-read-and-ssrf-vulnerability-threat-alert/
    - https://mp.weixin.qq.com/s?__biz=Mzg3NDU2MTg0Ng==&mid=2247484117&idx=1&sn=2fdab8cbe4b873f8dd8abb35d935d186
    - https://github.com/murataydemir/CVE-2021-27905
author: '@gott_cyber'
date: 2022-12-11
modified: 2023-03-24
tags:
    - attack.initial-access
    - attack.t1190
    - cve.2021-27905
    - detection.emerging-threats
logsource:
    category: webserver
detection:
    selection_request1:
        cs-uri-query|contains|all:
            - '/solr/'
            - '/debug/dump?'
            - 'param=ContentStream'
        sc-status: 200
    selection_request2:
        cs-method: 'GET'
        cs-uri-query|contains|all:
            - '/solr/'
            - 'command=fetchindex'
            - 'masterUrl='
        sc-status: 200
    condition: 1 of selection_*
falsepositives:
    - Vulnerability Scanners
level: medium

False positives

  • Vulnerability Scanners

References

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