mailcow-dockerized: Improper Neutralization of Special Elements used in an OS Command
CVE-2022-31138 is a high-severity improper neutralization of special elements used in an OS command vulnerability in mailcow-dockerized from Mailcow, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected mailcow-dockerized versions: < 2022-06a. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 3.28% chance of exploitation within 30 days, higher than 89% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Mailcow to 2022-06a or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Mailcow | mailcow-dockerized | < 2022-06a | Not stated |
| Mailcow | Mailcow | before 2022-06a | 2022-06a |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | CNA (github.com) |
| CVSS 3.1 | 8.8 | High | NVD |
| CVSS 2.0 | 9.0 | High | NVD |
Official description
mailcow is a mailserver suite. Prior to mailcow-dockerized version 2022-06a, an extended privilege vulnerability can be exploited by manipulating the custom parameters regexmess, skipmess, regexflag, delete2foldersonly, delete2foldersbutnot, regextrans2, pipemess, or maxlinelengthcmd to execute arbitrary code. Users should update their mailcow instances with the `update.sh` script in the mailcow root directory to 2022-06a or newer to receive a patch for this issue. As a temporary workaround, the Syncjob ACL can be removed from all mailbox users, preventing changes to those settings.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Special Elements used in an OS Command
The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command before it is sent to a downstream component.
How developers prevent this class of flaw
- If at all possible, use library calls rather than external processes to recreate the desired functionality.
- For any data that will be used to generate a command to be executed, keep as much of that data out of external control as possible. For example, in web applications, this may require storing the data locally in the session's state instead of sending it out to the client in a hidden form field.
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
More Improper Neutralization of Special Elements used in an OS Command vulnerabilities (CWE-78)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- github.com/mailcow/mailcow-dockerized/security/advisories/GHSA-vx9w-h33p-5vhcMitigation, Third Party Advisory
Patches and release notes
- github.com/mailcow/mailcow-dockerized/commit/d373164e13a14e058f82c9f1918a5612f375a9f9Third Party Advisory
- github.com/mailcow/mailcow-dockerized/releases/tag/2022-06aRelease Notes, Third Party Advisory
Technical write-ups (may include proof of concept)
- github.com/ly1g3/Mailcow-CVE-2022-31138Exploit, Third Party Advisory
Other vulnerabilities in mailcow-dockerized
- 9.1 Critical severity
- 7.4 High severity
- 7.0 High severity
- 8.9 High severity
- 9.3 Critical severity
- 7.2 High severity
Recent Improper Neutralization of Special Elements used in an OS Command vulnerabilities
- 9.8 Critical severity
- 8.8 High severity
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
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