CVE-2015-2740 in Firefox
Summary
by MITRE
Buffer overflow in the nsXMLHttpRequest::AppendToResponseText function in Mozilla Firefox before 39.0, Firefox ESR 31.x before 31.8 and 38.x before 38.1, and Thunderbird before 38.1 might allow remote attackers to cause a denial of service or have unspecified other impact via unknown vectors.
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Analysis
by VulDB Data Team • 10/22/2024
The vulnerability identified as CVE-2015-2740 represents a critical buffer overflow condition within Mozilla Firefox's XMLHTTP request handling mechanism. This flaw exists in the nsXMLHttpRequest::AppendToResponseText function, which is responsible for processing HTTP response data in web applications. The buffer overflow occurs when the application attempts to write data beyond the allocated memory boundaries, potentially leading to memory corruption and system instability. The vulnerability affects multiple versions of Firefox including the mainstream 39.0 release and the extended support release versions 31.8 and 38.1, as well as Thunderbird versions prior to 38.1, indicating a widespread impact across Mozilla's browser ecosystem.
The technical implementation of this vulnerability stems from inadequate bounds checking within the XMLHTTP request processing pipeline. When an attacker crafts a malicious HTTP response containing oversized data payloads, the AppendToResponseText function fails to properly validate the data length before copying it into a fixed-size buffer. This memory management failure allows attackers to overwrite adjacent memory locations, potentially corrupting critical application data structures or executing arbitrary code. The vulnerability manifests through unknown vectors, suggesting that multiple attack pathways could exploit this buffer overflow condition, making it particularly dangerous for security professionals to defend against. According to CWE classification, this represents a classic buffer overflow vulnerability categorized under CWE-121, which specifically addresses stack-based buffer overflow conditions.
The operational impact of CVE-2015-2740 extends beyond simple denial of service scenarios to potentially enable remote code execution and system compromise. Attackers could leverage this vulnerability to crash browser processes, leading to denial of service conditions that disrupt user productivity and access to web applications. More concerning is the potential for unspecified other impacts that may include privilege escalation, data theft, or complete system compromise depending on the execution environment. The vulnerability's presence in both Firefox and Thunderbird applications means that attackers could target email clients and web browsers simultaneously, increasing the attack surface and potential damage. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1059, which covers command and scripting interpreter usage, as attackers might exploit the memory corruption to execute malicious payloads through compromised browser processes.
Mitigation strategies for CVE-2015-2740 require immediate patch deployment across all affected Mozilla products, with security teams prioritizing updates to Firefox 39.0, Firefox ESR 31.8, Firefox ESR 38.1, and Thunderbird 38.1 releases. Organizations should implement network-based protections such as web application firewalls and intrusion detection systems to monitor for suspicious HTTP response patterns that might indicate exploitation attempts. Browser hardening measures including sandboxing, privilege separation, and memory protection mechanisms should be enabled to limit the potential damage from successful exploitation. Security administrators should also establish monitoring procedures to detect unusual browser crash patterns or memory allocation behaviors that could indicate exploitation of this buffer overflow condition. Regular security assessments and vulnerability scanning should be conducted to identify systems that may have been compromised through this vulnerability, while incident response protocols should be updated to address potential memory corruption attacks targeting browser applications.