CVE-2016-1950 in iPlanet Web Server
Summary
by MITRE
Heap-based buffer overflow in Mozilla Network Security Services (NSS) before 3.19.2.3 and 3.20.x and 3.21.x before 3.21.1, as used in Mozilla Firefox before 45.0 and Firefox ESR 38.x before 38.7, allows remote attackers to execute arbitrary code via crafted ASN.1 data in an X.509 certificate.
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Analysis
by VulDB Data Team • 10/23/2024
The vulnerability identified as CVE-2016-1950 represents a critical heap-based buffer overflow within Mozilla Network Security Services NSS library, affecting multiple versions of the security framework that underpins Firefox and other Mozilla products. This flaw exists in the ASN.1 parsing functionality responsible for processing X.509 certificates, making it particularly dangerous as certificate validation is a fundamental security operation in TLS/SSL communications. The vulnerability specifically impacts NSS versions prior to 3.19.2.3, 3.20.x, and 3.21.x before 3.21.1, while simultaneously affecting Firefox versions before 45.0 and Firefox ESR 38.x before 38.7, creating a widespread attack surface across numerous browser installations.
The technical nature of this vulnerability stems from improper bounds checking during the parsing of ASN.1 encoded data within X.509 certificates. When the NSS library encounters malformed or crafted ASN.1 structures, it fails to properly validate the buffer sizes before copying data into heap-allocated memory regions. This allows attackers to overflow buffer boundaries and potentially overwrite adjacent memory locations, leading to arbitrary code execution. The flaw operates at the intersection of multiple security domains including certificate validation, memory management, and cryptographic protocol handling, making it particularly insidious as it can be triggered during normal TLS handshake operations when certificates are processed.
The operational impact of this vulnerability extends far beyond simple code execution, as it represents a complete compromise of the affected system's security model. Attackers can leverage this flaw by constructing malicious X.509 certificates that, when processed by vulnerable browsers, trigger the buffer overflow and allow remote code execution with the privileges of the affected application. This capability enables attackers to perform man-in-the-middle attacks, execute arbitrary commands, steal sensitive data, or establish persistent access to systems. The vulnerability's remote exploitability means that attackers do not need physical access to target systems and can exploit it through standard web browsing activities, making it particularly dangerous in enterprise and consumer environments.
Mitigation strategies for CVE-2016-1950 primarily focus on immediate software updates and patches, as the most effective defense against this vulnerability is upgrading to patched versions of NSS, Firefox, and related products. Organizations should prioritize updating their browser installations and any applications that depend on vulnerable NSS versions, following the remediation guidance provided by Mozilla and security vendors. Additional protective measures include implementing certificate pinning mechanisms, monitoring for suspicious certificate usage, and deploying network-based intrusion detection systems to detect potential exploitation attempts. This vulnerability aligns with CWE-121 heap-based buffer overflow and maps to ATT&CK technique T1059 for execution through compromised applications, highlighting the need for comprehensive security hygiene practices including regular patch management and application security monitoring.