CVE-2017-2624

low-risk
Published 2018-07-27

It was found that xorg-x11-server before 1.19.0 including uses memcmp() to check the received MIT cookie against a series of valid cookies. If the cookie is correct, it is allowed to attach to the Xorg session. Since most memcmp() implementations return after an invalid byte is seen, this causes a time difference between a valid and invalid byte, which could allow an efficient brute force attack.

Do I need to act?

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0.05% chance of exploitation
EPSS score — low exploit probability
-
Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
5
CVSS 5.9/10 Medium
LOCAL / HIGH complexity

Affected Products (2)

Affected Vendors

Debian X.Org

References (16)

Third Party Advisory http://www.securityfocus.com/bid/96480
Third Party Advisory http://www.securitytracker.com/id/1037919
Exploit https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2017-2624
Patch https://gitlab.freedesktop.org/xorg/xserver/commit/d7ac755f0b618eb1259d93c8a16ec...
Third Party Advisory https://lists.debian.org/debian-lts-announce/2017/11/msg00032.html
Third Party Advisory https://security.gentoo.org/glsa/201704-03
Third Party Advisory https://security.gentoo.org/glsa/201710-30
Exploit https://www.x41-dsec.de/lab/advisories/x41-2017-001-xorg/
Third Party Advisory http://www.securityfocus.com/bid/96480
Third Party Advisory http://www.securitytracker.com/id/1037919
Exploit https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2017-2624
Patch https://gitlab.freedesktop.org/xorg/xserver/commit/d7ac755f0b618eb1259d93c8a16ec...
Third Party Advisory https://lists.debian.org/debian-lts-announce/2017/11/msg00032.html
Third Party Advisory https://security.gentoo.org/glsa/201704-03
Third Party Advisory https://security.gentoo.org/glsa/201710-30
Exploit https://www.x41-dsec.de/lab/advisories/x41-2017-001-xorg/
22
/ 100
low-risk
Severity 15/34 · Moderate
Exploitability 0/34 · Minimal
Exposure 7/34 · Low