CVE-2013-1620 in Enterprise Manager Ops Center
Summary
by MITRE
The TLS implementation in Mozilla Network Security Services (NSS) does not properly consider timing side-channel attacks on a noncompliant MAC check operation during the processing of malformed CBC padding, which allows remote attackers to conduct distinguishing attacks and plaintext-recovery attacks via statistical analysis of timing data for crafted packets, a related issue to CVE-2013-0169.
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Analysis
by VulDB Data Team • 03/03/2022
The vulnerability identified as CVE-2013-1620 represents a critical weakness in the TLS implementation within Mozilla Network Security Services NSS library, which forms the foundation of numerous security protocols across the internet. This flaw specifically targets the handling of Cipher Block Chaining padding during the processing of malformed packets, creating a pathway for sophisticated attackers to exploit timing side-channel vulnerabilities that compromise the integrity of encrypted communications. The issue stems from the NSS library's failure to properly manage the timing variations that occur during MAC (Message Authentication Code) verification operations, particularly when encountering non-compliant padding structures that violate standard TLS protocols.
The technical exploitation of this vulnerability occurs through careful statistical analysis of timing data collected from network traffic, enabling attackers to distinguish between different padding scenarios and ultimately recover plaintext information from encrypted communications. This timing side-channel attack exploits the fundamental weakness in the NSS implementation where the time required to process malformed CBC padding varies predictably based on whether the padding is valid or invalid. Attackers can leverage this timing variation to perform distinguishing attacks that separate valid from invalid padding, eventually leading to plaintext recovery through statistical analysis of multiple timing measurements. The vulnerability operates at the protocol level where the TLS handshake and data encryption/decryption processes occur, making it particularly dangerous as it can be exploited against any system relying on NSS for secure communications.
The operational impact of CVE-2013-1620 extends far beyond simple data confidentiality breaches, as it fundamentally undermines the trust model that secure communications depend upon. Systems utilizing NSS for TLS implementations become vulnerable to sophisticated attacks that can decrypt sensitive information without requiring direct access to encryption keys or certificates. This vulnerability affects a wide range of applications and services that rely on Mozilla NSS, including web browsers, email clients, and server applications, potentially exposing personal data, financial information, and corporate secrets. The attack requires only network access and the ability to observe timing variations, making it particularly dangerous as it can be executed remotely by attackers positioned anywhere along the communication path. The vulnerability's relationship to CVE-2013-0169 demonstrates a broader pattern of timing side-channel weaknesses in TLS implementations that affect multiple security components within the same ecosystem.
Mitigation strategies for CVE-2013-1620 require immediate patching of affected NSS versions and implementation of proper timing constant operations throughout the cryptographic processing pipeline. Organizations should prioritize updating their NSS libraries to versions that address the timing side-channel vulnerabilities by ensuring that MAC verification operations take constant time regardless of padding validity. The recommended approach involves implementing constant-time comparison algorithms and eliminating any conditional branches that depend on padding validation results during cryptographic operations. Security teams should also consider network-level monitoring for unusual timing patterns that might indicate exploitation attempts, as well as implementing proper key rotation and certificate management practices to minimize the impact of potential compromises. This vulnerability aligns with CWE-327, which specifically addresses weak cryptographic algorithms and implementations, and relates to ATT&CK technique T1552.001 for unsecured credentials and T1071.001 for application layer protocol usage, highlighting the multi-faceted nature of the security implications and the need for comprehensive defensive measures across multiple security domains.