Description
OpenSSH-portable (OpenSSH) 3.6.1p1 and earlier with PAM support enabled immediately sends an error message when a user does not exist, which allows remote attackers to determine valid usernames via a timing attack.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | openssh | 1:3.8.1p1-8.sarge.4 | — |
| Debian 13 | openssh | 1:3.8.1p1-8.sarge.4 | — |
| Debian 12 | openssh | 1:3.8.1p1-8.sarge.4 | — |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Metasploit 1 module
-
SSH Username Enumeration
auxiliary/scanner/ssh/ssh_enumusers
Exploit-DB 3
- Portable OpenSSH 3.6.1p-PAM/4.1-SuSE - Timing Attack EDB-3303 · remote · Feb 13, 2007 · verified
- OpenSSH/PAM 3.6.1p1 - 'gossh.sh' Remote Users Ident EDB-26 · remote · May 2, 2003 · verified
- OpenSSH/PAM 3.6.1p1 - Remote Users Discovery Tool EDB-25 · remote · Apr 30, 2003 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 2
- ICSA-22-349-21 Siemens SCALANCE X-200RNA Switch Devices CISA ICS & IT advisories · Dec 13, 2022
- SSA-412672 SSA-412672: Multiple OpenSSL and OpenSSH Vulnerabilities in SCALANCE X-200RNA Switch Devices before V3.2.7 Siemens ProductCERT · Dec 13, 2022
References
- RHSA-2003:222 vendor-advisory
- 20030430 OpenSSH/PAM timing attack allows remote users identification mailing-list
- 7467 vdb-entry
- 20030806 [OpenPKG-SA-2003.035] OpenPKG Security Advisory (openssh) mailing-list
- RHSA-2003:224 vendor-advisory
- oval:org.mitre.oval:def:445 vdb-entry signature
- http://lab.mediaservice.net/advisory/2003-01-openssh.txt
- TLSA-2003-31 vendor-advisory
- 20030430 OpenSSH/PAM timing attack allows remote users identification mailing-list
- https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf