CVE-2011-0396 in Pix Firewall 520
Summary
by MITRE
Cisco Adaptive Security Appliances (ASA) 5500 series devices with software 8.0 before 8.0(5.23), 8.1 before 8.1(2.49), 8.2 before 8.2(4.1), and 8.3 before 8.3(2.13), when a Certificate Authority (CA) is configured, allow remote attackers to read arbitrary files via unspecified vectors, aka Bug ID CSCtk12352.
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Analysis
by VulDB Data Team • 01/26/2025
The vulnerability identified as CVE-2011-0396 affects Cisco Adaptive Security Appliances (ASA) 5500 series devices operating with specific software versions, representing a critical file disclosure flaw that could enable remote attackers to access sensitive system information. This vulnerability specifically impacts devices running ASA software versions 8.0 before 8.0(5.23), 8.1 before 8.1(2.49), 8.2 before 8.2(4.1), and 8.3 before 8.3(2.13). The flaw occurs when a Certificate Authority configuration is present on the device, creating an attack surface that allows unauthorized access to arbitrary files within the system's file structure. The vulnerability is categorized under CWE-22, which represents improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
The technical implementation of this vulnerability stems from inadequate input validation within the certificate handling mechanisms of the ASA software. When a Certificate Authority is configured, the system processes certificate-related requests without sufficient sanitization of file paths or proper access controls, allowing attackers to manipulate input parameters to traverse the file system and access files that should remain restricted. This flaw operates at the application layer and leverages the device's certificate management functionality as an attack vector, potentially exposing sensitive configuration files, private keys, and other system-critical data. The unspecified vectors mentioned in the description suggest that the attack could be executed through multiple pathways within the certificate processing workflow, making the vulnerability particularly difficult to defend against through simple network segmentation.
The operational impact of this vulnerability extends beyond simple information disclosure, as it could enable attackers to gain insights into the network infrastructure configuration and potentially extract cryptographic keys used for secure communications. Attackers could leverage this vulnerability to access system logs, configuration files containing administrative credentials, and certificate repositories that might contain private keys for SSL/TLS encryption. The exposure of such sensitive information could facilitate further attacks including man-in-the-middle attacks, certificate forgery, and unauthorized access to protected network resources. This vulnerability directly impacts the integrity and confidentiality of the security infrastructure, as it undermines the trust model that the Certificate Authority is designed to establish. The vulnerability aligns with ATT&CK technique T1566, which covers credential harvesting through social engineering, but in this case represents an automated system-level attack vector rather than social engineering.
Organizations utilizing affected ASA devices should implement immediate mitigations including applying the relevant security patches provided by Cisco, which address the improper input validation issues in the certificate handling components. Network segmentation and access control measures should be enhanced to limit direct access to the ASA devices from untrusted networks, while monitoring systems should be configured to detect unusual file access patterns. Additionally, administrators should review and rotate any certificates or keys that may have been exposed through this vulnerability, and implement proper file access controls to minimize the potential impact of future similar vulnerabilities. The vulnerability demonstrates the critical importance of proper input validation and access control mechanisms in security appliances, as it represents a failure in the principle of least privilege that could allow attackers to escalate their privileges and access sensitive system resources.