CVE-2007-1051 in Personal Firewall
Summary
by MITRE
Comodo Firewall Pro (formerly Comodo Personal Firewall) 2.4.17.183 and earlier uses a weak cryptographic hashing function (CRC32) to identify trusted modules, which allows local users to bypass security protections by substituting modified modules that have the same CRC32 value.
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Analysis
by VulDB Data Team • 10/10/2017
Comodo Firewall Pro version 2.4.17.183 and earlier implementations suffer from a critical cryptographic weakness that undermines the security of their module trust verification system. The vulnerability stems from the use of CRC32 as the primary hashing algorithm for identifying and authenticating trusted security modules within the firewall's protection framework. This represents a fundamental flaw in the cryptographic design where a hash function specifically designed for error detection rather than security purposes is being employed for access control and module validation. The choice of CRC32 creates a significant attack surface since this algorithm is inherently vulnerable to collision attacks and lacks the necessary properties for cryptographic security. This weakness directly maps to CWE-327, which addresses the use of weak cryptographic algorithms, and specifically aligns with CWE-310 regarding cryptographic weaknesses in hash functions.
The technical exploitation of this vulnerability occurs through a straightforward collision attack methodology where malicious actors can create modified versions of legitimate security modules that produce identical CRC32 hash values to the original trusted modules. This collision capability allows attackers to substitute their malicious code for legitimate system components without triggering the firewall's security checks. The vulnerability operates at the kernel level within the firewall's module loading mechanism, where the system compares incoming module hashes against a trusted whitelist. Since CRC32 produces only 32 bits of output, the probability of finding collisions increases dramatically compared to cryptographic hash functions like SHA-256 or SHA-3. Attackers can leverage this weakness to bypass the firewall's module trust verification, potentially gaining unauthorized access to system resources and compromising the integrity of the security infrastructure.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete bypass of the firewall's protection mechanisms. Local users who can execute code on the system can exploit this weakness to load malicious modules that appear legitimate to the firewall's verification process, effectively creating a backdoor that operates under the firewall's trusted security context. This allows attackers to circumvent network traffic filtering, application control, and other security policies that the firewall is designed to enforce. The vulnerability affects the core security model of Comodo Firewall Pro by undermining the trust relationship between the firewall and its module components, potentially enabling attackers to modify or disable security features entirely. This represents a significant compromise in the principle of least privilege and can lead to complete system compromise when combined with other exploitation techniques. The impact is particularly severe because the firewall itself becomes the vector for bypassing its own security controls, creating a paradoxical situation where the security tool becomes the attack surface.
Mitigation strategies for this vulnerability require immediate remediation through software updates that replace the CRC32 hashing mechanism with cryptographically secure alternatives such as SHA-256 or SHA-3. Organizations should implement immediate monitoring for unauthorized module installations and establish integrity checking mechanisms that verify module signatures using proper cryptographic algorithms. The recommended approach involves upgrading to Comodo Firewall Pro versions that have addressed this vulnerability by implementing proper cryptographic hash functions and digital signatures for module verification. Security teams should also conduct comprehensive audits of system modules to identify any potentially compromised components and implement additional layers of security such as application whitelisting and integrity monitoring. This vulnerability demonstrates the critical importance of proper cryptographic implementation in security software and highlights the necessity of following established security standards such as those outlined in the NIST Cryptographic Standards and the OWASP Cryptographic Best Practices guidelines. The incident serves as a reminder of the fundamental principle that security-critical systems must employ robust cryptographic algorithms rather than those designed for performance or error detection purposes alone, as the consequences of cryptographic weakness in security software can be catastrophic to overall system security posture.