CVE-2010-4819 in X.Org
Summary
by MITRE
The ProcRenderAddGlyphs function in the Render extension (render/render.c) in X.Org xserver 1.7.7 and earlier allows local users to read arbitrary memory and possibly cause a denial of service (server crash) via unspecified vectors related to an "input sanitization flaw."
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Analysis
by VulDB Data Team • 12/13/2021
The vulnerability identified as CVE-2010-4819 resides within the X.Org xserver implementation of the Render extension, specifically in the ProcRenderAddGlyphs function located in render/render.c. This flaw represents a critical input sanitization issue that affects versions 1.7.7 and earlier of the xserver component. The vulnerability manifests as a local privilege escalation vector that enables attackers with access to the system to potentially read arbitrary memory locations and cause system instability through server crashes. The nature of this vulnerability places it squarely within the category of memory corruption flaws that can be exploited to gain unauthorized information access or disrupt system operations.
The technical exploitation of this vulnerability stems from inadequate input validation within the ProcRenderAddGlyphs function, which processes glyph data for the Render extension. When processing certain malformed or unexpected input parameters, the function fails to properly sanitize the data before using it in memory operations. This input sanitization flaw creates a pathway for attackers to manipulate memory access patterns and potentially read beyond allocated memory boundaries. The vulnerability's classification aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-129, which covers insufficient validation of array indices. The attack surface is particularly concerning because it operates within the core graphics server component, providing access to memory that may contain sensitive information or system resources.
Operationally, this vulnerability presents significant risks to systems running affected xserver versions, particularly those with multiple users or shared environments where local privilege escalation could occur. The potential for arbitrary memory reading means that attackers could extract confidential information from memory, including passwords, cryptographic keys, or other sensitive data that might be stored in accessible memory regions. Additionally, the possibility of causing denial of service through server crashes represents a serious operational impact that could disrupt graphics services and potentially affect other system components that depend on the X server. The vulnerability's local nature means that exploitation does not require network access, making it particularly dangerous in multi-user environments or systems where local access is possible.
The mitigation strategies for CVE-2010-4819 primarily involve upgrading to patched versions of the X.Org xserver where the input sanitization flaws have been addressed. System administrators should prioritize updating their xserver installations to versions that contain the appropriate fixes for the ProcRenderAddGlyphs function. Additionally, implementing proper access controls and limiting local user access to graphics services can help reduce the attack surface. The vulnerability's characteristics align with ATT&CK technique T1068, which involves the use of local privilege escalation techniques, and T1499, which covers network denial of service attacks. Organizations should also consider monitoring for unusual memory access patterns or system instability that might indicate exploitation attempts, particularly in environments where multiple users have local access to graphics services. The remediation process should include thorough testing of updated xserver versions to ensure compatibility with existing applications and services that depend on the Render extension functionality.