PT-2023-9380 · Shadow+4 · Shadow+4
Tom Neaves
·
Published
2023-04-14
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Updated
2026-01-21
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CVE-2023-29383
CVSS v3.1
3.3
Low
| Vector | AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N |
Name of the Vulnerable Software and Affected Versions
Shadow version 4.13
Description
The issue is related to insufficient neutralization of special elements in a request, which can be exploited to impact data integrity. In Shadow 4.13, it is possible to inject control characters into fields provided to the SUID program
chfn (change finger). Although direct exploitation is not possible due to block lists, an adversary can misrepresent the /etc/passwd file when viewed. By using r manipulations and Unicode characters to work around blocking of the : character, it is possible to give the impression that a new user has been added. This could lead to a social-engineered denial of service, where a system administrator takes the system offline after being convinced that a rogue user account exists.Recommendations
For Shadow version 4.13, consider disabling the
chfn function until a patch is available to prevent potential manipulation of the /etc/passwd file. Restrict access to the chfn program to minimize the risk of exploitation. Avoid using the chfn program to modify user accounts until the issue is resolved. At the moment, there is no information about a newer version that contains a fix for this vulnerability.Exploit
DoS
Out of bounds Read
Special Elements Injection
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Related Identifiers
Affected Products
Alt Linux
Astra Linux
Debian
Shadow
Suse