CVE-2021-3634

Name
CVE-2021-3634
Description
A flaw has been found in libssh in versions prior to 0.9.6. The SSH protocol keeps track of two shared secrets during the lifetime of the session. One of them is called secret_hash and the other session_id. Initially, both of them are the same, but after key re-exchange, previous session_id is kept and used as an input to new secret_hash. Historically, both of these buffers had shared length variable, which worked as long as these buffers were same. But the key re-exchange operation can also change the key exchange method, which can be based on hash of different size, eventually creating "secret_hash" of different size than the session_id has. This becomes an issue when the session_id memory is zeroed or when it is used again during second key re-exchange.
NVD Severity
unknown
Other trackers
Mailing lists
Exploits
Forges
GitHub (code, issues), Aports (code, issues)

References

Type URI
MISC https://bugzilla.redhat.com/show_bug.cgi?id=1978810
DEBIAN https://www.debian.org/security/2021/dsa-4965
Mailing List https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SVWAAB2XMKEUMPMDALINKAA4U2QM4LNG/
Mailing List https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/JKYD3ZRAMDAQX3ZW6THHUF3GXN7FF6B4/
Third Party Advisory https://security.netapp.com/advisory/ntap-20211004-0003/
Mailing List https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DRK67AJCWYYVAGF5SGAHNZXCX3PN3ZFP/
Patch https://www.oracle.com/security-alerts/cpujan2022.html
secalert@redhat.com https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DRK67AJCWYYVAGF5SGAHNZXCX3PN3ZFP/
secalert@redhat.com https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JKYD3ZRAMDAQX3ZW6THHUF3GXN7FF6B4/
secalert@redhat.com https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SVWAAB2XMKEUMPMDALINKAA4U2QM4LNG/
secalert@redhat.com https://security.gentoo.org/glsa/202312-05

Match rules

CPE URI Source package Min version Max version
cpe:2.3:a:libssh:libssh:*:*:*:*:*:*:*:* libssh >= None < 0.9.6
cpe:2.3:a:libssh:libssh:*:*:*:*:*:*:*:* libssh >= 0.9.1 < 0.9.6

Vulnerable and fixed packages

Source package Branch Version Maintainer Status
libssh 3.14-community 0.9.6-r0 Natanael Copa <ncopa@alpinelinux.org> fixed
libssh 3.11-main 0.9.4-r1 Natanael Copa <ncopa@alpinelinux.org> possibly vulnerable