CVE-2023-29383
Publication date 14 April 2023
Last updated 24 July 2024
Ubuntu priority
Cvss 3 Severity Score
In Shadow 4.13, it is possible to inject control characters into fields provided to the SUID program chfn (change finger). Although it is not possible to exploit this directly (e.g., adding a new user fails because \n is in the block list), it is possible to misrepresent the /etc/passwd file when viewed. Use of \r manipulations and Unicode characters to work around blocking of the : character make it possible to give the impression that a new user has been added. In other words, an adversary may be able to convince a system administrator to take the system offline (an indirect, social-engineered denial of service) by demonstrating that "cat /etc/passwd" shows a rogue user account.
Status
Package | Ubuntu Release | Status |
---|---|---|
shadow | 24.10 oracular |
Not affected
|
24.04 LTS noble |
Not affected
|
|
22.04 LTS jammy |
Vulnerable
|
|
20.04 LTS focal |
Vulnerable
|
|
18.04 LTS bionic |
Vulnerable
|
|
16.04 LTS xenial |
Vulnerable
|
|
14.04 LTS trusty |
Vulnerable
|
Severity score breakdown
Parameter | Value |
---|---|
Base score | 3.3 · Low |
Attack vector | Local |
Attack complexity | Low |
Privileges required | Low |
User interaction | None |
Scope | Unchanged |
Confidentiality | None |
Integrity impact | Low |
Availability impact | None |
Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N |
References
Other references
- https://github.com/shadow-maint/shadow/pull/687
- https://www.trustwave.com/en-us/resources/security-resources/security-advisories/?fid=31797
- https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/cve-2023-29383-abusing-linux-chfn-to-misrepresent-etc-passwd/
- https://www.cve.org/CVERecord?id=CVE-2023-29383