gnome-screensaver before 2.28.2 allows physically proximate attackers to bypass screen locking and access an unattended workstation by moving the mouse position to an external monitor and then disconnecting that monitor.

Multiple vulnerabilities has been discovered and corrected in gnome-screensaver :

gnome-screensaver 2.28.0 does not resume adherence to its activation settings after an inhibiting application becomes unavailable on the session bus, which allows physically proximate attackers to access an unattended workstation on which screen locking had been intended (CVE-2009-4641).

gnome-screensaver before 2.28.2 allows physically proximate attackers to bypass screen locking and access an unattended workstation by moving the mouse position to an external monitor and then disconnecting that monitor (CVE-2010-0414).

This update provides gnome-screensaver 2.28.3, which is not vulnerable to these issues.

gnome-screensaver currently doesn't deal with monitors getting removed properly. If the unlock dialog is on the removed monitor then the unlock dialog and its associated keyboard grab are not moved to an existing monitor when the monitor removal is processed. This means that users can gain access to the locked system by placing the mouse pointer on an external monitor and then disconnect the external monitor. https://bugzilla.gnome.org/show_bug.cgi?id=609337

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.

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.

It was discovered that gnome-screensaver did not correctly handle monitor hotplugging. An attacker with physical access could cause gnome-screensaver to crash and gain access to the locked session.

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.

ID	Name	Product	Family	Severity
48174	Mandriva Linux Security Advisory : gnome-screensaver (MDVSA-2010:040)	Nessus	Mandriva Local Security Checks	high
47263	Fedora 12 : gnome-screensaver-2.28.2-1.fc12 (2010-1556)	Nessus	Fedora Local Security Checks	high
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
44586	Ubuntu 9.10 : gnome-screensaver vulnerability (USN-898-1)	Nessus	Ubuntu Local Security Checks	high

Detections

Analytics

CVE-2010-0414

medium

Tenable Plugins

high

high

high

high

high