| Name | CVE-2023-29383 |
| 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. |
| Source | CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| References | ELA-1220-1 |
| Debian Bugs | 1034482 |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| shadow (PTS) | jessie, jessie (lts) | 1:4.2-3+deb8u5 | vulnerable |
| stretch (security) | 1:4.4-4.1+deb9u1 | vulnerable | |
| stretch (lts), stretch | 1:4.4-4.1+deb9u2 | fixed | |
| buster, buster (lts) | 1:4.5-1.1+deb10u1 | fixed | |
| bullseye | 1:4.8.1-1 | vulnerable | |
| bookworm | 1:4.13+dfsg1-1 | vulnerable | |
| sid, trixie | 1:4.16.0-5 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| shadow | source | stretch | 1:4.4-4.1+deb9u2 | ELA-1220-1 | ||
| shadow | source | buster | 1:4.5-1.1+deb10u1 | ELA-1220-1 | ||
| shadow | source | (unstable) | 1:4.13+dfsg1-2 | 1034482 |
[bookworm] - shadow <no-dsa> (Minor issue)
[bullseye] - shadow <no-dsa> (Minor issue)
[buster] - shadow <no-dsa> (Minor issue)
https://github.com/shadow-maint/shadow/pull/687
Fixed by: https://github.com/shadow-maint/shadow/commit/e5905c4b84d4fb90aefcd96ee618411ebfac663d (4.14.0-rc1)
Regression fix: https://github.com/shadow-maint/shadow/commit/2eaea70111f65b16d55998386e4ceb4273c19eb4 (4.14.0-rc1)
https://www.trustwave.com/en-us/resources/security-resources/security-advisories/?fid=31797
https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/cve-2023-29383-abusing-linux-chfn-to-misrepresent-etc-passwd/
[jessie] - shadow <no-dsa> (Minor issue)