The kex_input_kexinit function in kex.c in OpenSSH 6.x and 7.x through 7.3 allows remote attackers to cause a denial of service (memory consumption) by sending many duplicate KEXINIT requests. NOTE: a third party reports that OpenSSH upstream does not consider this as a security issue.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Openssh | Openbsd | 6.8 (including) | 6.8 (including) |
| Openssh | Openbsd | 6.9 (including) | 6.9 (including) |
| Openssh | Openbsd | 7.0 (including) | 7.0 (including) |
| Openssh | Openbsd | 7.1 (including) | 7.1 (including) |
| Openssh | Openbsd | 7.2 (including) | 7.2 (including) |
| Openssh | Openbsd | 7.3 (including) | 7.3 (including) |
| Openssh | Ubuntu | esm-infra-legacy/trusty | * |
| Openssh | Ubuntu | esm-infra/xenial | * |
| Openssh | Ubuntu | precise | * |
| Openssh | Ubuntu | precise/esm | * |
| Openssh | Ubuntu | trusty | * |
| Openssh | Ubuntu | trusty/esm | * |
| Openssh | Ubuntu | vivid/stable-phone-overlay | * |
| Openssh | Ubuntu | vivid/ubuntu-core | * |
| Openssh | Ubuntu | xenial | * |
| Openssh | Ubuntu | yakkety | * |
References
- http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/kex.c.diff?r1=1.126\u0026r2=1.127\u0026f=h
- http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/kex.c?rev=1.127\u0026content-type=text/x-cvsweb-markup
- http://www.openwall.com/lists/oss-security/2016/10/19/3
- http://www.openwall.com/lists/oss-security/2016/10/20/1
- http://www.securityfocus.com/bid/93776
- http://www.securitytracker.com/id/1037057
- https://bugzilla.redhat.com/show_bug.cgi?id=1384860
- https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
- https://ftp.openbsd.org/pub/OpenBSD/patches/6.0/common/013_ssh_kexinit.patch.sig
- https://github.com/openssh/openssh-portable/commit/ec165c392ca54317dbe3064a8c200de6531e89ad
- https://security.FreeBSD.org/advisories/FreeBSD-SA-16:33.openssh.asc
- https://security.gentoo.org/glsa/201612-18
- https://security.netapp.com/advisory/ntap-20180201-0001/
- http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/kex.c.diff?r1=1.126\u0026r2=1.127\u0026f=h
- http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/kex.c?rev=1.127\u0026content-type=text/x-cvsweb-markup
- http://www.openwall.com/lists/oss-security/2016/10/19/3
- http://www.openwall.com/lists/oss-security/2016/10/20/1
- http://www.securityfocus.com/bid/93776
- http://www.securitytracker.com/id/1037057
- https://bugzilla.redhat.com/show_bug.cgi?id=1384860
- https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
- https://ftp.openbsd.org/pub/OpenBSD/patches/6.0/common/013_ssh_kexinit.patch.sig
- https://github.com/openssh/openssh-portable/commit/ec165c392ca54317dbe3064a8c200de6531e89ad
- https://security.FreeBSD.org/advisories/FreeBSD-SA-16:33.openssh.asc
- https://security.gentoo.org/glsa/201612-18
- https://security.netapp.com/advisory/ntap-20180201-0001/