CVE-2013-2000 in libXxf86dga
Summary
by MITRE
Multiple buffer overflows in X.org libXxf86dga 1.1.3 and earlier allow X servers to cause a denial of service (crash) and possibly execute arbitrary code via crafted length or index values to the (1) XDGAQueryModes and (2) XDGASetMode functions.
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Analysis
by VulDB Data Team • 05/14/2021
The vulnerability identified as CVE-2013-2000 represents a critical buffer overflow issue within the X.org libXxf86dga library version 1.1.3 and earlier implementations. This flaw exists in the X Window System's graphics subsystem and specifically affects the XDGAQueryModes and XDGASetMode functions that handle graphics mode queries and settings. The vulnerability stems from inadequate input validation and bounds checking within these functions, creating opportunities for malicious actors to manipulate memory structures through crafted parameter values. Such buffer overflows occur when programs write more data to a buffer than it can safely hold, potentially leading to memory corruption that manifests as application crashes or more severe security implications.
The technical exploitation of this vulnerability relies on the manipulation of length or index values passed to the affected X protocol functions. When an X server processes these malformed parameters, the library fails to properly validate the input data against predetermined buffer boundaries, allowing attackers to overwrite adjacent memory locations. This memory corruption can result in immediate application termination through segmentation faults or more insidiously enable arbitrary code execution if the overwritten memory contains executable code pointers or control structures. The vulnerability's impact extends beyond simple denial of service as it could potentially allow privilege escalation or remote code execution depending on the execution context and system configuration.
From an operational standpoint, this vulnerability poses significant risks to X Window System environments including desktop workstations, servers, and embedded systems that utilize the affected graphics libraries. The attack surface encompasses any system running X servers that interact with the libXxf86dga library, particularly affecting Linux distributions and Unix-like systems that depend on X.org for graphical interfaces. The vulnerability's exploitation requires an attacker to have access to the X server environment or the ability to send malicious X protocol requests, making it particularly concerning for multi-user systems or networked environments where X11 forwarding is enabled. Security implications include potential system compromise, data integrity violations, and service disruption across graphical interfaces.
Mitigation strategies for CVE-2013-2000 should prioritize immediate patching of affected libXxf86dga library versions to the latest stable releases that contain proper bounds checking and input validation mechanisms. System administrators should implement network segmentation to limit X server access and disable unnecessary X11 forwarding capabilities where possible. Additionally, monitoring for suspicious X protocol activity and implementing proper access controls can help detect potential exploitation attempts. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and maps to ATT&CK techniques involving privilege escalation and code injection through memory corruption vulnerabilities. Organizations should also consider implementing application whitelisting policies and regular security assessments to identify and remediate similar buffer overflow vulnerabilities in their X Window System implementations.