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.
Advisories
Source ID Title
Debian DLA Debian DLA DLA-4130-1 shadow security update
EUVD EUVD EUVD-2023-32955 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.
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 11 Jul 2025 13:45:00 +0000

Type Values Removed Values Added
Metrics epss

{'score': 0.00026}

epss

{'score': 0.00033}


Thu, 06 Feb 2025 22:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-125
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2025-02-06T21:23:31.283Z

Reserved: 2023-04-05T00:00:00.000Z

Link: CVE-2023-29383

cve-icon Vulnrichment

Updated: 2024-08-02T14:07:45.784Z

cve-icon NVD

Status : Modified

Published: 2023-04-14T22:15:07.680

Modified: 2025-02-06T22:15:35.057

Link: CVE-2023-29383

cve-icon Redhat

Severity : Moderate

Publid Date: 2023-04-15T00:00:00Z

Links: CVE-2023-29383 - Bugzilla

cve-icon OpenCVE Enrichment

No data.