CVE-2013-6050 in Links
Summary
by MITRE
Integer overflow in Links before 2.8 allows remote attackers to cause a denial of service (crash) via crafted HTML tables.
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Analysis
by VulDB Data Team • 06/02/2021
The vulnerability identified as CVE-2013-6050 represents a critical integer overflow flaw within the Links web browser software version 2.7 and earlier. This vulnerability specifically affects the handling of HTML table structures and demonstrates how improper input validation can lead to system instability. The Links browser, being a text-based web client designed for terminal environments, processes HTML content through a parsing engine that fails to properly validate table dimensions and related numerical values during rendering operations. This flaw exists in the core HTML parsing and rendering components of the software, creating a condition where crafted malicious HTML table structures can trigger arithmetic overflow conditions within the application's memory management systems.
The technical execution of this vulnerability occurs when the Links browser encounters HTML tables with deliberately crafted dimensions or cell counts that exceed the maximum value representable by the integer data types used in the parsing logic. When these oversized table specifications are processed, the integer overflow causes the application to allocate insufficient memory or corrupt memory structures, ultimately resulting in a crash or application termination. The vulnerability is classified as a denial of service condition because it allows remote attackers to remotely execute commands that force the browser to cease operation without requiring any privileged access or authentication. This type of vulnerability falls under CWE-190, Integer Overflow or Wraparound, which specifically addresses situations where integer arithmetic operations produce results that exceed the maximum value representable by the data type, leading to unpredictable behavior and potential system compromise.
The operational impact of CVE-2013-6050 extends beyond simple service disruption as it represents a fundamental security weakness in the browser's input handling capabilities. Remote attackers can exploit this vulnerability from any location without requiring local access or user interaction beyond visiting a malicious webpage containing the crafted HTML table content. The vulnerability affects systems running Links versions prior to 2.8, making it particularly concerning for environments where automated updates are not implemented or where legacy systems continue to operate. This flaw creates opportunities for attackers to perform persistent denial of service attacks against users who rely on the Links browser for web access, potentially disrupting critical business operations or research activities. The vulnerability demonstrates the importance of proper integer validation in web browser implementations and aligns with ATT&CK technique T1499.004, which covers network denial of service attacks targeting application-level vulnerabilities.
Mitigation strategies for this vulnerability primarily focus on immediate software updates and patches to version 2.8 or later, which contain the necessary fixes to properly handle integer overflow conditions during HTML table processing. Organizations should implement comprehensive patch management procedures to ensure all instances of the Links browser are updated promptly, as the vulnerability affects the core rendering engine and cannot be effectively mitigated through configuration changes alone. Additionally, administrators should consider implementing web content filtering mechanisms that can identify and block HTML content containing suspicious table structures, though this approach provides only partial protection as the vulnerability can be triggered through various HTML table formatting techniques. Network-level protections such as intrusion detection systems can be configured to monitor for patterns associated with this specific vulnerability, but the most effective defense remains the immediate application of vendor-provided security patches. The vulnerability also highlights the importance of conducting regular security assessments of web browser implementations and the need for thorough input validation testing to prevent similar issues from emerging in other components of the software stack.