Shadow 4.13 chfn injection

Summaryinfo

A vulnerability marked as problematic has been reported in Shadow 4.13. This affects an unknown function of the component chfn. This manipulation causes injection. The identification of this vulnerability is CVE-2023-29383. The attack can only be executed locally. There is no exploit available. Applying a patch is the recommended action to fix this issue.

Detailsinfo

A vulnerability was found in Shadow 4.13. It has been declared as problematic. Affected by this vulnerability is an unknown code of the component chfn. The manipulation with an unknown input leads to a injection vulnerability. The CWE definition for the vulnerability is CWE-74. 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. As an impact it is known to affect integrity, and availability. The summary by CVE is:

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.

The weakness was shared 04/15/2023. The advisory is shared at github.com. This vulnerability is known as CVE-2023-29383 since 04/05/2023. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1055 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 234692 (Debian dla-4130 : login - security update), which helps to determine the existence of the flaw in a target environment.

Applying the patch e5905c4b84d4fb90aefcd96ee618411ebfac663d is able to eliminate this problem. The bugfix is ready for download at github.com.

The vulnerability is also documented in the databases at Tenable (234692) and EUVD (EUVD-2023-32955). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Name

• Shadow

Version

• 4.13

License

• open-source

CPE 2.3info

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• 🔍

CPE 2.2info

• 🔍
• 🔍

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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