CVE-2013-7220 in gnome-shell
Summary
by MITRE
js/ui/screenShield.js in GNOME Shell (aka gnome-shell) before 3.8 allows physically proximate attackers to execute arbitrary commands by leveraging an unattended workstation with the keyboard focus on the Activities search.
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Analysis
by VulDB Data Team • 05/12/2026
The vulnerability identified as CVE-2013-7220 resides within the GNOME Shell user interface component known as js/ui/screenShield.js which governs the screen locking mechanism in the GNOME desktop environment. This flaw affects versions of GNOME Shell prior to 3.8 and represents a significant security weakness that exploits the trust relationship between the desktop environment and user interactions. The vulnerability specifically targets unattended workstations where the keyboard focus remains on the Activities search interface, creating an exploitable condition that requires only physical proximity to the affected system. This attack vector demonstrates a fundamental flaw in the security model of the desktop environment's lock screen implementation.
The technical exploitation mechanism leverages a design oversight in how GNOME Shell handles keyboard input when the screen is locked. When a workstation is left unattended with the keyboard focus on the Activities search field, the system fails to properly validate or restrict input that could trigger command execution. The vulnerability stems from insufficient input sanitization and access control mechanisms within the screen shield component, allowing attackers to bypass normal security boundaries. This represents a classic case of insufficient input validation where user-provided data is not properly filtered or checked before being processed. The flaw operates at the application layer and directly impacts the desktop environment's security posture, with the potential for privilege escalation depending on the user context.
The operational impact of this vulnerability extends beyond simple command execution to represent a serious compromise of desktop security. An attacker with physical access to an unattended workstation can leverage this vulnerability to execute arbitrary commands with the privileges of the logged-in user, potentially leading to data theft, system modification, or further network infiltration. The vulnerability is particularly dangerous in enterprise environments where multiple users share workstations or where security policies require unattended systems to maintain locked states. The attack requires minimal sophistication and only physical proximity, making it particularly concerning for organizations that do not implement proper workstation security policies. This vulnerability directly impacts the principle of least privilege and demonstrates how desktop security mechanisms can be bypassed through careful exploitation of interface design flaws.
Mitigation strategies for CVE-2013-7220 primarily focus on upgrading to GNOME Shell version 3.8 or later where the vulnerability has been addressed through improved input validation and access control mechanisms. Organizations should implement comprehensive workstation security policies that require automatic screen locking after periods of inactivity and ensure that all systems are updated with the latest security patches. The vulnerability aligns with CWE-20, which describes improper input validation, and can be mapped to ATT&CK technique T1068, which covers exploitation of remote services and local system vulnerabilities. Additionally, system administrators should consider implementing additional security controls such as automatic screen locking, disabling keyboard shortcuts during lock states, and ensuring proper user session management to prevent exploitation of similar vulnerabilities in other desktop environments.