CVE-2021-32749
Publication date 16 July 2021
Last updated 24 July 2024
Ubuntu priority
Cvss 3 Severity Score
fail2ban is a daemon to ban hosts that cause multiple authentication errors. In versions 0.9.7 and prior, 0.10.0 through 0.10.6, and 0.11.0 through 0.11.2, there is a vulnerability that leads to possible remote code execution in the mailing action mail-whois. Command `mail` from mailutils package used in mail actions like `mail-whois` can execute command if unescaped sequences (`\n~`) are available in "foreign" input (for instance in whois output). To exploit the vulnerability, an attacker would need to insert malicious characters into the response sent by the whois server, either via a MITM attack or by taking over a whois server. The issue is patched in versions 0.10.7 and 0.11.3. As a workaround, one may avoid the usage of action `mail-whois` or patch the vulnerability manually.
Status
Package | Ubuntu Release | Status |
---|---|---|
fail2ban | 24.10 oracular |
Not affected
|
24.04 LTS noble |
Not affected
|
|
22.04 LTS jammy |
Not affected
|
|
20.04 LTS focal |
Fixed 0.11.1-1ubuntu0.1~esm1
|
|
18.04 LTS bionic |
Fixed 0.10.2-2ubuntu0.1~esm1
|
|
16.04 LTS xenial |
Fixed 0.9.3-1ubuntu0.1~esm1
|
|
14.04 LTS trusty |
Fixed 0.8.11-1ubuntu0.1~esm1
|
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Get Ubuntu ProSeverity score breakdown
Parameter | Value |
---|---|
Base score | 8.1 · High |
Attack vector | Network |
Attack complexity | High |
Privileges required | None |
User interaction | None |
Scope | Unchanged |
Confidentiality | High |
Integrity impact | High |
Availability impact | High |
Vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |
References
Related Ubuntu Security Notices (USN)
- USN-5232-1
- Fail2ban vulnerability
- 12 September 2022
Other references
- https://github.com/fail2ban/fail2ban/security/advisories/GHSA-m985-3f3v-cwmm
- https://github.com/fail2ban/fail2ban/commit/2ed414ed09b3bb4c478abc9366a1ff22024a33c9 (0.9)
- https://github.com/fail2ban/fail2ban/commit/410a6ce5c80dd981c22752da034f2529b5eee844 (0.10, 0.11, 1.0)
- https://github.com/fail2ban/fail2ban/commit/410a6ce5c80dd981c22752da034f2529b5eee844
- https://github.com/fail2ban/fail2ban/commit/2ed414ed09b3bb4c478abc9366a1ff22024a33c9
- https://www.cve.org/CVERecord?id=CVE-2021-32749