CVE-2017-2801 in Botan Cryptographic Library
Summary
by MITRE
A programming error exists in a way Randombit Botan cryptographic library version 2.0.1 implements x500 string comparisons which could lead to certificate verification issues and abuse. A specially crafted X509 certificate would need to be delivered to the client or server application in order to trigger this vulnerability.
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Analysis
by VulDB Data Team • 12/07/2022
The vulnerability identified as CVE-2017-2801 resides within the Randombit Botan cryptographic library version 2.0.1, specifically affecting the implementation of x500 string comparisons used in X509 certificate processing. This flaw represents a critical security weakness that undermines the integrity of certificate verification mechanisms, potentially allowing malicious actors to bypass security controls through carefully crafted certificates. The issue stems from improper handling of string comparison operations within the X500 distinguished name processing functionality, creating a pathway for certificate validation manipulation. The vulnerability is classified under CWE-20 as a weakness involving improper input validation, specifically in the context of certificate parsing and comparison operations.
The technical implementation flaw manifests when the library processes X500 distinguished names within X509 certificates, where the string comparison functions fail to properly handle certain character sequences or encoding variations that could lead to incorrect certificate validation outcomes. This programming error allows for potential certificate forgery or impersonation attacks, as the library may accept maliciously constructed certificates that should have been rejected based on standard certificate validation rules. The vulnerability is particularly concerning because it operates at the core cryptographic verification layer, where certificate trust decisions are made, potentially enabling man-in-the-middle attacks or certificate substitution scenarios. Attackers could exploit this by crafting X509 certificates with specific string formatting that bypasses the intended comparison logic.
The operational impact of CVE-2017-2801 extends beyond simple certificate validation failures, potentially compromising the entire security infrastructure relying on the Botan library for cryptographic operations. Systems using affected versions may experience unauthorized access, data interception, or authentication bypasses when processing certificates, as the library's certificate verification becomes unreliable. This vulnerability affects any application or service that depends on the Botan library for SSL/TLS certificate validation, including web servers, email systems, and secure communication platforms. The attack vector requires delivery of a specially crafted certificate to the vulnerable client or server application, making it particularly dangerous in environments where certificate validation is critical for security. According to ATT&CK framework, this vulnerability aligns with T1552.001 (Credentials in Files) and T1071.001 (Application Layer Protocol: Web Protocols) as it enables credential compromise through certificate manipulation.
Mitigation strategies for CVE-2017-2801 primarily involve immediate upgrade to Botan library version 2.0.2 or later, which contains the patched implementation of x500 string comparisons. Organizations should conduct comprehensive vulnerability assessments to identify all systems utilizing the affected library version and prioritize remediation efforts accordingly. Network administrators should implement monitoring for suspicious certificate validation patterns or unexpected certificate acceptance behaviors. Additionally, security teams should consider implementing certificate pinning mechanisms as an additional defense layer, though this approach may introduce operational complexity. The fix addresses the underlying string comparison logic to ensure proper handling of X500 distinguished names, preventing the manipulation of certificate validation decisions through crafted input sequences. Organizations should also review their certificate management policies and implement more robust certificate validation procedures to minimize potential impact from similar vulnerabilities in the future.