CVE-2011-0766 in OTP
Summary
by MITRE
The random number generator in the Crypto application before 2.0.2.2, and SSH before 2.0.5, as used in the Erlang/OTP ssh library before R14B03, uses predictable seeds based on the current time, which makes it easier for remote attackers to guess DSA host and SSH session keys.
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Analysis
by VulDB Data Team • 08/03/2024
The vulnerability described in CVE-2011-0766 represents a critical weakness in cryptographic random number generation within the Erlang/OTP ssh library ecosystem. This flaw affects versions prior to R14B03 and specifically impacts the Crypto application versions before 2.0.2.2 and SSH versions before 2.0.5. The core issue stems from the predictable seeding of random number generators, which fundamentally undermines the security guarantees that cryptographic systems rely upon for their integrity and confidentiality.
The technical implementation of this vulnerability involves the use of time-based seeds for random number generation, a practice that violates fundamental cryptographic principles outlined in standards such as NIST SP 800-90A and CWE-330. When random number generators are seeded with predictable values like timestamps, attackers can reproduce the exact sequence of random numbers generated by the system. This predictability directly enables the exploitation of DSA host keys and SSH session keys, creating a pathway for unauthorized access and session hijacking. The vulnerability operates at the cryptographic primitive level, affecting the generation of key material that should remain unpredictable and secure.
The operational impact of this vulnerability extends beyond simple key compromise, creating cascading security risks within systems that rely on the affected Erlang/OTP components. Remote attackers can leverage this weakness to perform session hijacking attacks, bypass authentication mechanisms, and potentially gain unauthorized access to systems. The attack surface is particularly concerning given that SSH is a fundamental protocol for secure remote access, and DSA host keys are critical for server authentication. This vulnerability aligns with ATT&CK technique T1566.001 for credential access through exploitation of weak cryptographic implementations and represents a significant concern for organizations using Erlang-based systems for secure communications.
Mitigation strategies for this vulnerability require immediate patching of affected systems to versions R14B03 or later, which address the predictable seeding issue in the random number generation algorithms. Organizations should also implement monitoring for suspicious authentication patterns and consider implementing additional security controls such as key rotation procedures and enhanced intrusion detection systems. The fix typically involves updating the underlying cryptographic libraries and ensuring that random number generators are properly seeded with truly random data rather than predictable time-based values. System administrators should also review their cryptographic configurations and ensure that all components are updated to versions that properly address this weakness, as the vulnerability can persist even when other security measures are in place.