CVE-2016-6515
Description
The auth_password function in auth-passwd.c in sshd in OpenSSH before 7.3 does not limit password lengths for password authentication, which allows remote attackers to cause a denial of service (crypt CPU consumption) via a long string.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
Exploits
Public proof-of-concept code below. AS-IS, for defenders and authorised testing only.
Exploit-DB
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| sles | affected | | |
| fedora | 24 | affected | |
| debian | bookworm | fixed | 1:7.3p1-1 |
| debian | bullseye | fixed | 1:7.3p1-1 |
| debian | forky | fixed | 1:7.3p1-1 |
| debian | sid | fixed | 1:7.3p1-1 |
| debian | trixie | fixed | 1:7.3p1-1 |
Application impact
| Vendor | Product | Versions | Fixed |
|---|---|---|---|
| openbsd | openssh | {"endIncluding":"7.2"} | |
References
- http://openwall.com/lists/oss-security/2016/08/01/2
- http://packetstormsecurity.com/files/140070/OpenSSH-7.2-Denial-Of-Service.html
- http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.html
- http://www.securityfocus.com/bid/92212
- http://www.securitytracker.com/id/1036487
- https://access.redhat.com/errata/RHSA-2017:2029
- https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
- https://cert-portal.siemens.com/productcert/pdf/ssa-676336.pdf
- https://github.com/openssh/openssh-portable/commit/fcd135c9df440bcd2d5870405ad3311743d78d97
- https://lists.debian.org/debian-lts-announce/2018/09/msg00010.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X2L6RW34VFNXYNVVN2CN73YAGJ5VMTFU/
- https://security.FreeBSD.org/advisories/FreeBSD-SA-17:06.openssh.asc
- https://security.netapp.com/advisory/ntap-20171130-0003/
- https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03779en_us
- https://www.exploit-db.com/exploits/40888/
- https://www.suse.com/security/cve/CVE-2016-6515.html
- https://security-tracker.debian.org/tracker/CVE-2016-6515
CWEs
CWE-20
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.