CVE-2010-2640 in Evince
Summary
by MITRE
Array index error in the PK font parser in the dvi-backend component in Evince 2.32 and earlier allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted font in conjunction with a DVI file that is processed by the thumbnailer.
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Analysis
by VulDB Data Team • 10/11/2021
The vulnerability identified as CVE-2010-2640 represents a critical array index error within the PostScript font parser component of Evince's dvi-backend functionality. This flaw exists in Evince versions 2.32 and earlier, where the application fails to properly validate array bounds when processing font data within DVI files. The vulnerability specifically affects the thumbnailer component which processes DVI documents to generate previews, making it particularly dangerous as it can be triggered during routine document handling operations.
The technical implementation of this vulnerability stems from inadequate input validation in the font parsing logic that handles PostScript font data structures. When a maliciously crafted DVI file contains malformed font information, the parser attempts to access memory locations beyond the allocated array boundaries. This memory corruption occurs during the processing of font metrics and glyph data, where the application assumes certain array dimensions without proper bounds checking. The flaw falls under CWE-129, which specifically addresses insufficient bounds checking, and can be classified as a buffer overflow vulnerability that may lead to memory corruption. The vulnerability demonstrates characteristics of CWE-787, which describes out-of-bounds write operations, as the parser writes to memory locations that exceed the allocated buffer space.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to potentially enable remote code execution. Attackers can craft DVI files containing specially constructed font data that triggers the array index error when processed by Evince's thumbnailer. This creates a vector for both service disruption and arbitrary code execution, particularly when users open or preview DVI documents in environments where thumbnail generation occurs automatically. The vulnerability affects users who may encounter malicious DVI files in email attachments, shared network drives, or web-based document repositories. The threat landscape is further complicated by the fact that thumbnail generation often occurs automatically in file managers and document viewers, making user interaction minimal or non-existent during exploitation.
Mitigation strategies for CVE-2010-2640 should prioritize immediate patching of Evince installations to versions 2.32.1 or later where the font parsing logic has been corrected to include proper array bounds checking. System administrators should implement strict file validation policies for DVI files, particularly in environments where users may encounter untrusted documents. Network-level defenses should include DVI file content filtering and sandboxing mechanisms to prevent automatic thumbnail generation of suspicious documents. Organizations should also consider disabling automatic thumbnail generation for potentially malicious file types and implementing user awareness training about the risks of opening untrusted DVI files. The vulnerability's classification under ATT&CK technique T1203, which covers exploitation of remote services, indicates that this flaw could be leveraged in broader attack chains targeting document processing systems. Additionally, implementing runtime protections such as address space layout randomization and stack canaries can help mitigate potential exploitation attempts, though the primary defense remains proper bounds checking in the font parsing implementation.