Vulnerability · Published Feb 3, 2023 · Assigned by mitre
CVE-2023-25136
Medium 6.5
In plain English
A medium-severity double free in the openssh package (AlmaLinux). Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 89.8% (higher than 99.8% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Official description
OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling. This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in the default configuration, to jump to any location in the sshd address space. One third-party report states "remote code execution is theoretically possible."
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:9 | openssh | 8.7p1-29.el9_2 | ALSA-2023:2645 |
| AlmaLinux:9 | openssh-askpass | 8.7p1-29.el9_2 | ALSA-2023:2645 |
| AlmaLinux:9 | openssh-clients | 8.7p1-29.el9_2 | ALSA-2023:2645 |
| AlmaLinux:9 | openssh-keycat | 8.7p1-29.el9_2 | ALSA-2023:2645 |
| AlmaLinux:9 | openssh-server | 8.7p1-29.el9_2 | ALSA-2023:2645 |
| AlmaLinux:9 | pam_ssh_agent_auth | 0.10.4-5.29.el9_2 | ALSA-2023:2645 |
| Debian:12 | openssh | 1:9.2p1-1 | DEBIAN-CVE-2023-25136 |
| Debian:13 | openssh | 1:9.2p1-1 | DEBIAN-CVE-2023-25136 |
| Debian:14 | openssh | 1:9.2p1-1 | DEBIAN-CVE-2023-25136 |
Affected products (as reported)
Weakness: CWE-415
References
- https://ftp.openbsd.org/pub/OpenBSD/patches/7.2/common/017_sshd.patch.sig
- https://www.openwall.com/lists/oss-security/2023/02/02/2
- https://bugzilla.mindrot.org/show_bug.cgi?id=3522
- https://github.com/openssh/openssh-portable/commit/486c4dc3b83b4b67d663fb0fa62bc24138ec3946
- https://jfrog.com/blog/openssh-pre-auth-double-free-cve-2023-25136-writeup-and-proof-of-concept/
- https://news.ycombinator.com/item?id=34711565
- [oss-security] 20230213 Re: double-free vulnerability in OpenSSH server 9.1 (CVE-2023-25136) mailing-list
- [oss-security] 20230222 Re: double-free vulnerability in OpenSSH server 9.1 (CVE-2023-25136) mailing-list
- [oss-security] 20230222 Re: Re: double-free vulnerability in OpenSSH server 9.1 (CVE-2023-25136) mailing-list
- [oss-security] 20230223 Re: Re: double-free vulnerability in OpenSSH server 9.1 (CVE-2023-25136) mailing-list
- [oss-security] 20230306 Re: Re: double-free vulnerability in OpenSSH server 9.1 (CVE-2023-25136) mailing-list
- [oss-security] 20230309 Re: Re: double-free vulnerability in OpenSSH server 9.1 (CVE-2023-25136) mailing-list
- https://security.netapp.com/advisory/ntap-20230309-0003/
- FEDORA-2023-1176c8b10c vendor-advisory
- FEDORA-2023-123647648e vendor-advisory
- GLSA-202307-01 vendor-advisory
- https://cert-portal.siemens.com/productcert/html/ssa-398330.html