CVE-2003-1096 in LEAP
Summary
by MITRE
The Cisco LEAP challenge/response authentication mechanism uses passwords in a way that is susceptible to dictionary attacks, which makes it easier for remote attackers to gain privileges via brute force password guessing attacks.
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Analysis
by VulDB Data Team • 11/18/2024
The Cisco LEAP challenge/response authentication mechanism represents a significant security vulnerability that fundamentally undermines the integrity of wireless network authentication systems. This flaw resides in the implementation of the Lightweight Extensible Authentication Protocol which was designed to provide secure authentication for wireless networks. The vulnerability specifically targets the password handling methodology within the LEAP framework, creating an exploitable weakness that directly impacts the security posture of networks relying on this authentication standard.
The technical flaw in CVE-2003-1096 stems from the insecure treatment of passwords within the LEAP protocol implementation. The mechanism fails to properly obscure or encrypt password information during the authentication exchange process, making it susceptible to dictionary attack vectors. This vulnerability manifests because the LEAP protocol does not adequately protect password credentials during transmission and validation phases, allowing attackers to capture authentication challenges and systematically test potential password guesses against the captured authentication data. The flaw essentially transforms what should be a secure multi-factor authentication process into a targetable weak point that can be exploited through automated brute force attacks.
The operational impact of this vulnerability extends beyond simple credential compromise to represent a fundamental threat to wireless network security infrastructure. Attackers can leverage the dictionary attack susceptibility to systematically guess passwords and gain unauthorized access to wireless networks, potentially leading to complete network compromise and lateral movement within organizational environments. This vulnerability particularly affects enterprise wireless networks that deployed Cisco access points and authentication servers, creating widespread security implications across multiple network segments. The ease with which attackers can exploit this weakness through automated tools means that even moderately complex passwords can be compromised within reasonable timeframes, rendering the authentication mechanism ineffective against determined adversaries.
Organizations affected by this vulnerability should implement immediate mitigation strategies including transitioning to more secure authentication protocols such as EAP-TLS or EAP-PEAP, which provide stronger encryption and authentication mechanisms. The implementation of additional security controls such as account lockout policies and increased authentication complexity requirements can help reduce the effectiveness of brute force attacks. Network administrators should also consider implementing network segmentation and monitoring solutions to detect unusual authentication patterns that might indicate exploitation attempts. From a compliance perspective, this vulnerability directly impacts adherence to security frameworks such as those outlined in the NIST Special Publication 800-46 and aligns with attack patterns documented in the MITRE ATT&CK framework under credential access and privilege escalation techniques.
The vulnerability demonstrates the critical importance of proper cryptographic implementation in authentication protocols and serves as a reminder that even widely deployed security standards can contain fundamental flaws. This weakness represents a classic example of insufficient entropy and poor key derivation practices that leave authentication systems vulnerable to automated attack vectors. Security professionals should view this vulnerability as a cautionary tale regarding the necessity of thorough security testing and validation of authentication mechanisms before deployment in production environments. The remediation process requires not only immediate protocol changes but also comprehensive network security assessments to identify potential exploitation and ensure that other systems do not exhibit similar weaknesses in their authentication implementations.