CVE-2009-2535 in Thunderbird
Summary
by MITRE
Mozilla Firefox before 2.0.0.19 and 3.x before 3.0.5, SeaMonkey, and Thunderbird allow remote attackers to cause a denial of service (memory consumption and application crash) via a large integer value for the length property of a Select object, a related issue to CVE-2009-1692.
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Analysis
by VulDB Data Team • 12/29/2024
This vulnerability affects Mozilla Firefox versions prior to 2.0.0.19 and 3.x versions prior to 3.0.5, along with SeaMonkey and Thunderbird email clients. The flaw resides in how these applications handle the length property of Select objects within HTML documents. When a malicious web page attempts to set an excessively large integer value for this property, the affected applications consume excessive memory resources and eventually crash. This represents a classic buffer overflow condition where the application fails to properly validate input parameters before processing them, leading to uncontrolled memory allocation and resource exhaustion.
The technical implementation of this vulnerability stems from inadequate bounds checking within the browser's HTML parsing and rendering engine. When processing Select elements, the applications do not properly validate the length property value, allowing attackers to specify arbitrary large integers that trigger memory allocation routines to allocate massive amounts of memory. This behavior aligns with CWE-129, which describes improper validation of length parameters, and CWE-770, which covers allocation of resources without proper limits. The vulnerability operates at the application layer and can be exploited through web-based attacks, making it particularly dangerous in modern browser environments where users frequently visit untrusted websites.
The operational impact of this vulnerability extends beyond simple denial of service conditions. Attackers can leverage this weakness to consume system resources and potentially cause application instability, leading to complete system crashes or unresponsiveness. In practical scenarios, this could allow malicious actors to disrupt user workflows, particularly in environments where these applications are used for critical tasks. The vulnerability's exploitation requires no special privileges and can be executed through standard web browsing activities, making it highly accessible to threat actors. This type of attack maps to ATT&CK technique T1499.004, which involves network denial of service attacks, and represents a significant risk to user productivity and system availability.
Mitigation strategies for this vulnerability include immediate patching of affected software versions, implementing web application firewalls to filter suspicious HTML content, and establishing monitoring systems to detect unusual memory consumption patterns. Organizations should also consider implementing browser hardening measures and restricting access to untrusted websites where possible. The most effective solution remains the timely application of security patches provided by the software vendors, as these updates contain proper bounds checking mechanisms that prevent the exploitation of malformed Select element properties. Regular security assessments and vulnerability scanning should be conducted to identify and remediate similar issues across the organization's software portfolio.