CVE-2008-4061 in Firefox
Summary
by MITRE
Integer overflow in the MathML component in Mozilla Firefox before 2.0.0.17 and 3.x before 3.0.2, Thunderbird before 2.0.0.17, and SeaMonkey before 1.1.12 allows remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via an mtd element with a large integer value in the rowspan attribute, related to the layout engine.
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Analysis
by VulDB Data Team • 08/17/2019
The vulnerability described in CVE-2008-4061 represents a critical integer overflow flaw within the MathML rendering engine of several Mozilla-based applications including Firefox, Thunderbird, and SeaMonkey. This vulnerability specifically targets the layout engine's handling of mtd elements with excessively large integer values in the rowspan attribute, creating a condition where the application fails to properly validate input data before processing it. The flaw exists in versions prior to Firefox 2.0.0.17 and 3.x 3.0.2, Thunderbird 2.0.0.17, and SeaMonkey 1.1.12, indicating a widespread issue affecting multiple components of the Mozilla ecosystem. The integer overflow occurs during the parsing and rendering of mathematical markup language content, where the application attempts to allocate memory based on an invalid integer value, leading to unpredictable behavior.
The technical implementation of this vulnerability involves the manipulation of the MathML mtd element which is used to define table data cells within mathematical expressions. When a malicious actor crafts an mtd element with an extremely large integer value in the rowspan attribute, the application's layout engine processes this value without adequate bounds checking. This lack of input validation causes the integer overflow to occur during memory allocation calculations, where the large integer value wraps around to a small positive value or zero, resulting in insufficient memory allocation for the intended operation. The underlying issue stems from the absence of proper integer overflow detection mechanisms within the MathML parser, which is categorized under CWE-190 as an integer overflow or wraparound vulnerability.
The operational impact of this vulnerability manifests in two primary forms of exploitation that align with the ATT&CK framework's T1499 technique for network denial of service. The most immediate consequence is a denial of service condition where the application experiences memory corruption and subsequent crashes, effectively preventing legitimate users from accessing the affected functionality. However, the vulnerability's potential for arbitrary code execution cannot be dismissed, as the memory corruption resulting from the integer overflow may allow attackers to manipulate program execution flow. This dual nature of impact makes the vulnerability particularly dangerous as it can be leveraged for both service disruption and more sophisticated attack vectors. The attack requires remote code execution capabilities since the flaw is triggered through malformed MathML content delivered via web pages or email messages.
The mitigation strategies for this vulnerability primarily focus on immediate version updates to patched releases of the affected software components. Users should upgrade to Firefox 2.0.0.17 and 3.x 3.0.2, Thunderbird 2.0.0.17, and SeaMonkey 1.1.12, which contain fixes addressing the integer overflow condition in the MathML parser. Additionally, administrators should implement content filtering mechanisms to prevent the rendering of untrusted MathML content, particularly in environments where users may encounter maliciously crafted web pages. The fix typically involves implementing proper integer bounds checking before memory allocation operations and ensuring that the layout engine validates all integer attributes within MathML elements. Organizations should also consider implementing security monitoring to detect potential exploitation attempts through unusual memory allocation patterns or application crash events, as these may indicate successful exploitation of the integer overflow vulnerability.