Vulnerability Report

CVE-2023-29383

Title: Misrepresentation of /etc/passwd file leading to social-engineered DoS

Denial of Service

Proof Of Concept

No public PoC currently indexed for CVE-2023-29383.

CWE Category CWE-125
Published Date Apr 14, 2023
Modified Date Nov 03, 2025
Exploit Status Not Found
Score 3.3 CVSS v3.1
Exploit Probability (EPSS)
0.43%

Vulnerability Summary

CVE-2023-29383: 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.

Impacted Vendors

S
shadow_project 1
B
blade-group 1

Reference Links

https://github.com/shadow-maint/shadow/commit/e5905c4b84d4fb90aefcd96ee618411ebfac663d https://github.com/shadow-maint/shadow/pull/687 https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/cve-2023-29383-abusing-linux-chfn-to-misrepresent-etc-passwd/ https://www.trustwave.com/en-us/resources/security-resources/security-advisories/?fid=31797 https://github.com/shadow-maint/shadow/commit/e5905c4b84d4fb90aefcd96ee618411ebfac663d https://github.com/shadow-maint/shadow/pull/687 https://lists.debian.org/debian-lts-announce/2025/04/msg00026.html https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/cve-2023-29383-abusing-linux-chfn-to-misrepresent-etc-passwd/ https://www.trustwave.com/en-us/resources/security-resources/security-advisories/?fid=31797
CVSS v3.1
Source Entity [email protected]
Severity LOW
3.3
Attack Vector
LOCAL
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2023-29383 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data or affected products updated.

PUBLISHED

Vulnerability first announced in NVD.

Attack Vector Matrix

Access Vector LOCAL
Complexity LOW
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Affected Stack

No specific products linked.