CVE-2023-29383: shadow_project shadow Injection

Vulnerability summary

CVE-2023-29383 is a low (CVSS 3.3) Injection vulnerability in shadow_project shadow. EPSS estimates a 0.43% chance of exploitation in the next 30 days, higher than 35.4% of scored vulnerabilities. 2 public exploits are recorded.

Timeline

1. 14-04-2023
   PublishedVulnerability first disclosed.
2. 14-10-2026
   Last modifiedVulnerability information updated.

Description

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.

• CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.
• CWE-125Out-of-bounds ReadThe product reads data past the end, or before the beginning, of the intended buffer.