CVE-2005-1058 in IOS
Summary
by MITRE
Cisco IOS 12.2T, 12.3 and 12.3T, when processing an ISAKMP profile that specifies XAUTH authentication after Phase 1 negotiation, may not process certain attributes in the ISAKMP profile that specifies XAUTH, which allows remote attackers to bypass XAUTH and move to Phase 2 negotiations.
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Analysis
by VulDB Data Team • 07/02/2019
The vulnerability described in CVE-2005-1058 represents a critical weakness in Cisco IOS software versions 12.2T, 12.3, and 12.3T that affects the Internet Security Association and Key Management Protocol implementation. This flaw specifically impacts the processing of ISAKMP (Internet Security Association and Key Management Protocol) profiles during VPN authentication procedures, creating a significant security gap in the authentication mechanism that could allow unauthorized access to network resources.
The technical flaw manifests when the IOS software processes ISAKMP profiles that specify Extended Authentication (XAUTH) after the initial Phase 1 negotiation has been completed. During this process, the system fails to properly validate or process certain attributes contained within the ISAKMP profile that defines XAUTH authentication requirements. This incomplete attribute processing creates a condition where the authentication mechanism can be bypassed, allowing attackers to proceed directly to Phase 2 negotiations without proper authentication. The vulnerability stems from insufficient input validation and attribute processing within the ISAKMP profile handling code, which falls under CWE-20 as a weakness involving improper input validation.
The operational impact of this vulnerability is severe as it directly undermines the security posture of Cisco devices implementing IPsec VPNs. Attackers exploiting this weakness can bypass the extended authentication phase that should verify user credentials and permissions before establishing secure communication channels. This creates an opening for unauthorized network access, potentially allowing malicious actors to establish VPN connections with elevated privileges or access to sensitive network resources. The vulnerability specifically targets the XAUTH authentication mechanism, which is designed to provide additional user authentication beyond the initial ISAKMP Phase 1 authentication, making it a critical component of VPN security.
The security implications extend beyond simple access bypass as this vulnerability can be exploited to perform man-in-the-middle attacks, unauthorized network penetration, and potentially escalate privileges within the network infrastructure. The attack vector requires remote access to the vulnerable Cisco IOS device, making it particularly dangerous in environments where external connectivity is permitted. This weakness aligns with ATT&CK technique T1566, which covers credential harvesting through network sniffing and authentication bypass methods. Organizations using affected Cisco IOS versions face significant risk of unauthorized access to their network resources, particularly those relying on IPsec VPNs for secure remote access and site-to-site connections.
Mitigation strategies for this vulnerability include immediate deployment of Cisco IOS software updates and patches that address the ISAKMP profile attribute processing flaw. Network administrators should also implement additional security controls such as monitoring for unusual authentication patterns, implementing stricter access controls, and ensuring that only necessary services are exposed to external networks. The patching process should be prioritized based on the criticality of the affected network segments and the potential attack surface exposure. Organizations should also consider implementing network segmentation and additional authentication layers to reduce the impact if the vulnerability is exploited. Regular security assessments and vulnerability scanning should be conducted to identify and remediate similar weaknesses in the network infrastructure, as this vulnerability demonstrates the importance of proper input validation in security-critical network protocols.