gnome-screensaver 2.28.x before 2.28.3 does not properly synchronize the state of screen locking and the unlock dialog in situations involving a change to the number of monitors, which allows physically proximate attackers to bypass screen locking and access an unattended workstation by connecting and disconnecting monitors multiple times, a related issue to CVE-2010-0414.

gnome-screensaver can lose its keyboard grab when locked, exposing the system to intrusion by adding and removing monitors.

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

It was discovered that gnome-screensaver did not correctly lock all screens when monitors get hotplugged. An attacker with physical access could use this flaw to gain access to a locked session.
(CVE-2010-0285)

It was discovered that gnome-screensaver did not correctly handle keyboard grab when monitors get hotplugged. An attacker with physical access could use this flaw to gain access to a locked session. This issue only affected Ubuntu 9.10. (CVE-2010-0422).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

gnome-screensaver was updated to the stable release 2.28.3, fixing various bugs and security issues.

Following security issues have been fixed: When resuming a system gnome-screensaver does not lock external displays that got connected while the system was suspended (CVE-2010-0285: CVSS v2 Base Score:
5.6).

Additionally another bug in gnome-screensaver was fixed that allowed bypassing the unlock dialog by using a removable monitor.
(CVE-2010-0414: CVSS v2 Base Score: 6.2)

Pressing 'return' repeatedly caused a X error which terminated the lock and so allowed local users to access the underlying session. (no CVE yet)

CVE-2010-0422: gnome-screensaver can lose its keyboard grab when locked, exposing the system to intrusion by adding and removing monitors.

Ray Strode reports :

Under certain circumstances it is possible to circumvent the security of screen locking functionality of gnome-screensaver by changing the systems physical monitor configuration.

gnome-screensaver can lose its keyboard grab when locked, exposing the system to intrusion by adding and removing monitors.

ID	Name	Product	Family	Severity
47277	Fedora 12 : gnome-screensaver-2.28.3-1.fc12 (2010-1855)	Nessus	Fedora Local Security Checks	medium
45016	Ubuntu 8.10 / 9.04 / 9.10 : gnome-screensaver vulnerabilities (USN-907-1)	Nessus	Ubuntu Local Security Checks	medium
44622	openSUSE Security Update : gnome-screensaver (gnome-screensaver-1973)	Nessus	SuSE Local Security Checks	high
44599	FreeBSD : gnome-screensaver -- Multiple monitor hotplug issues (0a82ac0c-1886-11df-b0d1-0015f2db7bde)	Nessus	FreeBSD Local Security Checks	high

Detections

Analytics

CVE-2010-0422

medium

Tenable Plugins

medium

medium

high

high