CVE-2025-21117 in Avamar
Summary
by MITRE • 02/05/2025
Dell Avamar, version 19.4 or later, contains an access token reuse vulnerability in the AUI. A low privileged local attacker could potentially exploit this vulnerability, leading to fully impersonating the user.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 03/28/2025
The vulnerability identified as CVE-2025-21117 affects Dell Avamar version 19.4 and later implementations, specifically within the Administrative User Interface component. This access token reuse flaw represents a critical security weakness that undermines the authentication mechanisms designed to protect system access. The vulnerability resides in how the AUI manages and validates authentication tokens, creating an opportunity for malicious actors to exploit the system's trust model. The flaw allows an attacker with low privileged local access to potentially obtain and reuse valid access tokens, thereby enabling full impersonation of legitimate users within the system environment. This type of vulnerability directly impacts the integrity and confidentiality of the protected data and systems.
The technical implementation of this vulnerability stems from improper token lifecycle management within the AUI authentication framework. When users authenticate to the system, valid access tokens are generated and subsequently used for session management. However, the flaw allows for token reuse without proper validation checks, enabling an attacker to intercept, manipulate, or replay valid tokens obtained through legitimate means. This behavior aligns with CWE-306, which addresses missing authentication for critical functions, and CWE-307, which deals with excessive login attempts or weak session management. The vulnerability essentially creates a persistent access vector that bypasses normal authentication controls, allowing unauthorized access to system resources that should be restricted to authorized personnel.
The operational impact of this vulnerability extends beyond simple unauthorized access, potentially enabling attackers to perform administrative functions, modify system configurations, access sensitive data, and establish persistent footholds within the network. A low privileged local attacker who successfully exploits this vulnerability can effectively elevate their privileges and gain full control over the Avamar system. This type of attack vector is particularly concerning because it leverages legitimate system functionality to achieve unauthorized access, making detection more challenging. The attack pattern aligns with ATT&CK technique T1078.004, which covers valid accounts with compromised credentials, and T1566.001, involving spearphishing with social engineering. The implications for organizations using Dell Avamar systems include potential data breaches, system compromise, and unauthorized modification of backup and recovery operations that could severely impact business continuity.
Organizations should implement immediate mitigations including patching the system to the latest available version that addresses this vulnerability, implementing strict access controls and monitoring for unusual authentication patterns, and conducting thorough security assessments of the Avamar environment. The recommended approach involves disabling unnecessary authentication mechanisms, implementing token expiration policies, and establishing robust session management protocols. Security teams should also consider deploying network monitoring solutions to detect potential token reuse activities and establish incident response procedures for handling such security events. Additionally, organizations should review their access control policies and ensure that least privilege principles are properly enforced within the Avamar environment to minimize the potential impact of successful exploitation attempts.