CVE-2008-7224 in ELinks
Summary
by MITRE
Buffer overflow in entity_cache in ELinks before 0.11.4rc0 allows remote attackers to cause a denial of service (crash) via a crafted link.
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Analysis
by VulDB Data Team • 08/22/2021
The vulnerability identified as CVE-2008-7224 represents a critical buffer overflow condition within the entity_cache functionality of the ELinks web browser version 0.11.3 and earlier. This flaw resides in the handling of entity references within HTML documents, specifically when processing crafted links that contain malformed entity declarations. The buffer overflow occurs when the application attempts to store entity data in a fixed-size buffer without proper bounds checking, creating an exploitable condition that can be triggered remotely through maliciously constructed web content.
The technical implementation of this vulnerability demonstrates a classic stack-based buffer overflow scenario where the entity_cache function fails to validate the length of incoming entity data before copying it into a predetermined memory buffer. This condition typically arises when processing HTML entities such as numeric character references or named entities that exceed the allocated buffer space. The flaw operates under CWE-121 which categorizes stack-based buffer overflow conditions, making it susceptible to both denial of service attacks and potentially more severe exploitation if the application's memory layout allows for arbitrary code execution. The vulnerability specifically affects the HTML parsing engine's entity handling mechanism, which is fundamental to proper document rendering and processing.
From an operational perspective, this vulnerability presents a significant risk to users of ELinks versions prior to 0.11.4rc0 as remote attackers can craft malicious web pages containing specially formatted links that trigger the buffer overflow condition. When a user navigates to such a page or follows a crafted link, the browser crashes and terminates unexpectedly, resulting in a denial of service condition that disrupts normal browsing operations. The attack vector is particularly concerning because it requires no local privileges or user interaction beyond normal browsing behavior, making it an attractive target for automated exploitation campaigns. This vulnerability directly impacts the availability and reliability of the browser application, potentially affecting users in environments where ELinks serves as the primary web browsing solution.
Mitigation strategies for this vulnerability center on immediate software updates to ELinks version 0.11.4rc0 or later, which contains the necessary patches to address the buffer overflow condition. System administrators should prioritize deployment of these updates across all affected systems, particularly in enterprise environments where ELinks is widely used for web browsing or terminal-based applications. Additional protective measures include implementing web filtering solutions that can detect and block known malicious entity patterns, configuring browser security settings to limit entity processing, and establishing monitoring protocols to detect potential exploitation attempts. The vulnerability also highlights the importance of input validation and bounds checking in web browser implementations, aligning with ATT&CK technique T1203 which covers exploitation of software vulnerabilities. Organizations should conduct regular security assessments to identify similar buffer overflow conditions in other browser components and maintain updated threat intelligence to prevent exploitation of similar vulnerabilities in the broader software ecosystem.