CVE-2013-1984 in libXi
Summary
by MITRE
Multiple integer overflows in X.org libXi 1.7.1 and earlier allow X servers to trigger allocation of insufficient memory and a buffer overflow via vectors related to the (1) XGetDeviceControl, (2) XGetFeedbackControl, (3) XGetDeviceDontPropagateList, (4) XGetDeviceMotionEvents, (5) XIGetProperty, (6) XIGetSelectedEvents, (7) XGetDeviceProperties, and (8) XListInputDevices functions.
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Analysis
by VulDB Data Team • 05/14/2021
The vulnerability identified as CVE-2013-1984 represents a critical security flaw in the X.org libXi library version 1.7.1 and earlier, affecting the X Window System input handling mechanisms. This issue stems from multiple integer overflow conditions that occur during the processing of input device control functions within X servers. The flaw specifically impacts eight distinct functions including XGetDeviceControl, XGetFeedbackControl, XGetDeviceDontPropagateList, XGetDeviceMotionEvents, XIGetProperty, XIGetSelectedEvents, XGetDeviceProperties, and XListInputDevices, all of which are fundamental components for managing input devices in graphical environments. These functions are commonly used by X servers to query and control various input device parameters, making them prime targets for exploitation.
The technical nature of this vulnerability involves integer overflow conditions that lead to improper memory allocation calculations. When X servers process requests through these affected functions, the library fails to properly validate integer inputs before performing memory allocation operations. This results in the allocation of insufficient memory buffers that cannot accommodate the actual data being processed. The overflow condition occurs when integer arithmetic exceeds the maximum representable value, causing the system to allocate a smaller buffer than required. This fundamental flaw creates a predictable buffer overflow scenario where attacker-controlled data can overwrite adjacent memory regions, potentially leading to arbitrary code execution or system instability.
The operational impact of this vulnerability extends beyond simple memory corruption, as it enables remote attackers to potentially execute arbitrary code on systems running affected X servers. The attack vector requires an attacker to have access to an X server that utilizes the vulnerable libXi library, typically through network-based X11 connections or local access to graphical environments. When exploited, these integer overflows can lead to complete system compromise, denial of service conditions, or privilege escalation depending on the execution context. The vulnerability affects desktop environments, server systems, and any platform that relies on X Window System input handling, making it particularly dangerous in multi-user or networked environments where X11 forwarding is commonly used.
From a cybersecurity perspective, this vulnerability maps directly to CWE-190, which identifies integer overflow conditions as a primary source of memory corruption vulnerabilities. The attack pattern aligns with ATT&CK technique T1059.007 for command and scripting interpreter execution, as successful exploitation could lead to code execution within the X server process. Organizations using affected systems should prioritize immediate patching of libXi libraries to version 1.7.2 or later, which includes proper integer overflow checks and bounds validation. System administrators should also implement network segmentation to limit access to X servers and disable unnecessary X11 forwarding capabilities. Additional mitigations include monitoring for unusual X server memory allocation patterns and implementing intrusion detection systems that can identify potential exploitation attempts through malformed input device requests. The vulnerability demonstrates the critical importance of input validation in graphical system libraries and highlights the need for comprehensive security testing of core infrastructure components that handle user input.