Command execution via mailutils tilde escape parsing
Published Jul 16, 2021 · Updated Aug 3, 2024
Command injection in Fail2Ban 0.9.7 and earlier, 0.10.0 through 0.10.6, and 0.11.0 through 0.11.2 allows attackers to execute commands. The mail-whois action pipes attacker-influenced WHOIS output into GNU mailutils mail, which interprets newline-prefixed tilde escapes as shell operations. Exploitation requires mail-whois with mailutils and control of a WHOIS response, such as through a man-in-the-middle position or a controlled WHOIS server.
Summary
What happened
Command injection in Fail2Ban 0.9.7 and earlier, 0.10.0 through 0.10.6, and 0.11.0 through 0.11.2 allows attackers to execute commands. The mail-whois action pipes attacker-influenced WHOIS output into GNU mailutils mail, which interprets newline-prefixed tilde escapes as shell operations. Exploitation requires mail-whois with mailutils and control of a WHOIS response, such as through a man-in-the-middle position or a controlled WHOIS server.
The record
- CVE
- CVE-2021-32749
- Published
- Jul 16, 2021
- Updated
- Aug 3, 2024
- Vendor
- Fail2Ban
- Product
- Fail2Ban
- Classifications
- T1059
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 16, 2021CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 0.10.0, <= 0.10.6
- Affected versionversion=>= 0.11.0, <= 0.11.2
- Affected versionversion=<= 0.9.7
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Upstream mail-whois tilde-escape proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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