CVE-2013-1986 in libXrandr
Summary
by MITRE
Multiple integer overflows in X.org libXrandr 1.4.0 and earlier allow X servers to trigger allocation of insufficient memory and a buffer overflow via vectors related to the (1) XRRQueryOutputProperty and (2) XRRQueryProviderProperty functions.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 05/14/2021
The vulnerability identified as CVE-2013-1986 represents a critical security flaw within the X.org libXrandr library version 1.4.0 and earlier implementations. This issue affects the X Window System's ability to handle display configuration requests properly, creating potential pathways for malicious actors to exploit memory handling inconsistencies in graphical server environments. The vulnerability specifically targets the XRRQueryOutputProperty and XRRQueryProviderProperty functions, which are responsible for querying display output and provider properties within the X server architecture. These functions process data structures containing integer values that, when improperly validated, can lead to integer overflow conditions during memory allocation operations.
The technical exploitation of this vulnerability occurs when X servers receive specially crafted requests that manipulate integer values within the display property query mechanisms. When these integer values exceed their maximum representable range, they wrap around to negative values or extremely large numbers, causing the system to allocate insufficient memory buffers. This memory allocation failure directly results in buffer overflow conditions that can be leveraged by attackers to execute arbitrary code or cause system instability. The flaw operates at the intersection of memory management and input validation, where integer overflows in parameter processing lead to improper buffer sizing calculations. This vulnerability type aligns with CWE-190, which specifically addresses integer overflow conditions that can lead to memory corruption and arbitrary code execution.
The operational impact of CVE-2013-1986 extends beyond simple denial-of-service scenarios to encompass potential remote code execution capabilities within affected X server environments. Systems utilizing vulnerable libXrandr versions in graphical server configurations become susceptible to attacks that could compromise desktop environments, virtual machines, or remote desktop sessions. The vulnerability affects not only local systems but also networked X server implementations where external clients can submit malicious property queries. Attackers could exploit this weakness to gain elevated privileges, manipulate display configurations, or disrupt graphical user interfaces in ways that could impact productivity and security posture. This makes the vulnerability particularly dangerous in enterprise environments where X server implementations are common across various operating systems and desktop configurations.
Mitigation strategies for CVE-2013-1986 should prioritize immediate patching of affected libXrandr implementations to version 1.4.1 or later, which includes proper integer overflow protections and enhanced input validation mechanisms. System administrators should implement network segmentation to limit access to X server components and disable unnecessary X11 forwarding capabilities where possible. Security monitoring should focus on detecting unusual X server activity patterns, particularly around display property queries and memory allocation operations. The vulnerability demonstrates the importance of proper integer overflow protection in system libraries and highlights the need for robust input validation across all graphical interface components. Organizations should also consider implementing additional security controls such as mandatory access controls and privilege separation to limit the potential impact of successful exploitation attempts. This vulnerability serves as a reminder of the critical importance of maintaining up-to-date system libraries and the potential for seemingly minor flaws in core system components to create significant security risks. The issue also relates to ATT&CK technique T1068, which involves exploiting legitimate credentials and system access to gain privileges, as the vulnerability can enable attackers to escalate their access within graphical environments.