CVE-2021-24295: Spam protection, AntiSpam, FireWall by CleanTalk < 5.153.4 - Unauthenticated Blind SQL Injection

2025-08-01 CleanTalk PoC Public

Description

It was possible to exploit an Unauthenticated Time-Based Blind SQL Injection vulnerability in the Spam protection, AntiSpam, FireWall by CleanTalk WordPress Plugin before 5.153.4. The update_log function in lib/Cleantalk/ApbctWP/Firewall/SFW.php included a vulnerable query that could be injected via the User-Agent Header by manipulating the cookies set by the Spam protection, AntiSpam, FireWall by CleanTalk WordPress plugin before 5.153.4, sending an initial request to obtain a ct_sfw_pass_key cookie and then manually setting a separate ct_sfw_passed cookie and disallowing it from being reset.

PoC

id: CVE-2021-24295

info:
  name: Spam protection, AntiSpam, FireWall by CleanTalk < 5.153.4 - Unauthenticated Blind SQL Injection
  author: DhiyaneshDK
  severity: high
  description: |
    It was possible to exploit an Unauthenticated Time-Based Blind SQL Injection vulnerability in the Spam protection, AntiSpam, FireWall by CleanTalk WordPress Plugin before 5.153.4. The update_log function in lib/Cleantalk/ApbctWP/Firewall/SFW.php included a vulnerable query that could be injected via the User-Agent Header by manipulating the cookies set by the Spam protection, AntiSpam, FireWall by CleanTalk WordPress plugin before 5.153.4, sending an initial request to obtain a ct_sfw_pass_key cookie and then manually setting a separate ct_sfw_passed cookie and disallowing it from being reset.
  impact: |
    Unauthenticated attackers can extract database contents via time-based blind SQL injection through User-Agent header manipulation, potentially exposing all WordPress user data.
  remediation: Fixed in 5.153.4
  reference:
    - https://wpscan.com/vulnerability/152171fc-888c-4275-a118-5a1e664ef28b
    - https://github.com/20142995/nuclei-templates
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
    cvss-score: 7.5
    cve-id: CVE-2021-24295
    cwe-id: CWE-89
    epss-score: 0.04691
    epss-percentile: 0.91323
    cpe: cpe:2.3:a:cleantalk:spam_protection\,_antispam\,_firewall:*:*:*:*:*:wordpress:*:*
  metadata:
    verified: true
    max-request: 1
    vendor: cleantalk
    product: spam_protection\,_antispam\,_firewall
    framework: wordpress
    fofa-query: body="/plugin/cleantalk-spam-protect/"
  tags: cve,cve2021,wpscan,wordpress,wp,wp-plugin,cleantalk-spam-protect,sqli,passive,vkev,vuln

http:
  - raw:
      - |
        GET /wp-content/plugins/cleantalk-spam-protect/readme.txt HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: dsl
        dsl:
          - 'compare_versions(version, "< 5.153.4")'
          - 'contains(body, "Spam protection")'
          - 'status_code == 200'
        condition: and

    extractors:
      - type: regex
        name: version
        part: body
        group: 1
        internal: true
        regex:
          - "(?mi)Stable tag: ([0-9.]+)"
# digest: 4a0a0047304502201d770e3306dd25860e803509705fe84e41273a1fc17ab60e1ec1cc7782fee1dc022100c67773b091eeeb55a0a355222b61a05625b7d68fa5b7d8f2bc8f4127d89ebd7c:922c64590222798bb761d5b6d8e72950

# Visit https://trap.biu.life/ to view exploit trends for this vulnerability.

References

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