CVE-2015-7182 in Communications Messaging Server
Summary
by MITRE
Heap-based buffer overflow in the ASN.1 decoder in Mozilla Network Security Services (NSS) before 3.19.2.1 and 3.20.x before 3.20.1, as used in Firefox before 42.0 and Firefox ESR 38.x before 38.4 and other products, allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via crafted OCTET STRING data.
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Analysis
by VulDB Data Team • 10/23/2024
The vulnerability CVE-2015-7182 represents a critical heap-based buffer overflow within the ASN.1 decoder component of Mozilla Network Security Services NSS library. This flaw affects multiple versions of NSS prior to 3.19.2.1 and 3.20.1, impacting Firefox browsers before version 42.0 and Firefox ESR 38.x before 38.4, along with various other products that rely on NSS for security operations. The vulnerability stems from improper bounds checking during the processing of ASN.1 encoded data structures, specifically when handling OCTET STRING elements that contain malformed or excessively large data payloads. The issue falls under CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to write beyond allocated memory boundaries, potentially corrupting adjacent memory regions and leading to unpredictable behavior.
The technical exploitation of this vulnerability occurs when maliciously crafted ASN.1 OCTET STRING data is processed by the NSS library during certificate parsing or other cryptographic operations. When the decoder encounters oversized or malformed OCTET STRING elements, it fails to properly validate the data length against allocated buffer space, allowing attackers to overwrite adjacent heap memory locations. This memory corruption can manifest as application crashes during normal operation or potentially enable remote code execution if carefully crafted payload data can be used to overwrite function pointers or control structures within the heap. The vulnerability operates at the intersection of cryptographic protocol handling and memory management, making it particularly dangerous in security-sensitive contexts where ASN.1 decoding is performed on untrusted network data.
The operational impact of CVE-2015-7182 extends beyond simple denial of service conditions to potentially enable remote code execution, making it a severe threat to systems relying on NSS for secure communications. Attackers can leverage this vulnerability by constructing specially formatted ASN.1 structures that trigger the buffer overflow during certificate validation processes, which are commonly performed when establishing secure connections to web servers, email systems, or other network services. The vulnerability affects not only web browsers but also any application that utilizes NSS for cryptographic operations, including email clients, servers, and security appliances. This widespread impact is consistent with the ATT&CK technique T1203, which describes the exploitation of memory corruption vulnerabilities for code execution, and represents a classic example of how cryptographic library flaws can compromise entire application ecosystems.
Mitigation strategies for CVE-2015-7182 primarily focus on immediate version updates to patched NSS releases, specifically versions 3.19.2.1 and 3.20.1 or later. Organizations should prioritize updating all affected Firefox installations, including ESR versions, and ensure that any applications relying on NSS for security operations are upgraded to versions containing the fix. Additionally, implementing network-based protections such as intrusion detection systems that can identify and block malformed ASN.1 traffic patterns may provide temporary defense while full patches are deployed. Security teams should also consider monitoring for potential exploitation attempts through log analysis and implementing proper input validation at network boundaries where ASN.1 data is processed. The vulnerability demonstrates the importance of thorough memory safety testing in cryptographic libraries and highlights the need for regular security assessments of core security components that handle untrusted data inputs.