Dovecot: Improper Authentication
CVE-2022-30550 is a high-severity improper authentication vulnerability in Dovecot, 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. The record lists version 2.4.0 as the first without the flaw, so updating Dovecot to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 2.29% chance of exploitation within 30 days, higher than 84% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Dovecot to 2.4.0 or a later version.
- Read the advisory on dovecot.org for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Dovecot | Dovecot | 2.3 up to, but not including, 2.4.0; 2.2 | 2.4.0 |
| Debian | Debian Linux | 10.0 | Not stated |
Version data comes from NVD's product matching. 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 | NVD |
| CVSS 3.1 | 8.8 | High | CISA (ADP) |
Official description
An issue was discovered in the auth component in Dovecot 2.2 and 2.3 before 2.3.20. When two passdb configuration entries exist with the same driver and args settings, incorrect username_filter and mechanism settings can be applied to passdb definitions. These incorrectly applied settings can lead to an unintended security configuration and can permit privilege escalation in certain configurations. The documentation does not advise against the use of passdb definitions that have the same driver and args settings. One such configuration would be where an administrator wishes to use the same PAM configuration or passwd file for both normal and master users but use the username_filter setting to restrict which of the users is able to be a master user.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Authentication
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
How developers prevent this class of flaw
- Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
- openwall.com/lists/oss-security/2022/07/08/1Mailing List, Third Party Advisory
Third-party and government advisories
- lists.debian.org/debian-lts-announce/2022/09/msg00032.htmlMailing List, Third Party Advisory
- security.gentoo.org/glsa/202310-19Third Party Advisory
Other references
- dovecot.org/download/Product
Other vulnerabilities in Dovecot
- 9.1 Critical severity
- 7.5 High severity
- 7.5 High severity
- 8.2 High severity
- 7.5 High severity
- 7.5 High severity
Recent Improper Authentication vulnerabilities
- 7.8 High severity
- 7.5 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 8.1 High severity
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