CVE-2020-12254 in Avira
Summary
by MITRE
Avira Antivirus before 5.0.2003.1821 on Windows allows privilege escalation or a denial of service via abuse of a symlink.
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Analysis
by VulDB Data Team • 06/03/2024
The vulnerability identified as CVE-2020-12254 affects Avira Antivirus versions prior to 5.0.2003.1821 on Windows operating systems, representing a critical security flaw that enables unauthorized privilege escalation or denial of service attacks through improper symlink handling. This vulnerability exploits the software's insufficient validation of symbolic links during file operations, creating a pathway for malicious actors to manipulate system resources and potentially elevate their privileges beyond the intended user permissions.
The technical implementation of this vulnerability stems from the antivirus software's failure to properly validate or sanitize symbolic link references within its file processing mechanisms. When Avira Antivirus encounters files or directories that are symbolic links, the software does not adequately verify the legitimacy of these links before attempting to access or modify the target resources. This oversight allows attackers to create malicious symlinks that point to sensitive system files or directories, enabling them to either execute arbitrary code with elevated privileges or cause the antivirus service to crash through targeted denial of service attacks.
From an operational perspective, this vulnerability presents significant risks to enterprise environments where Avira Antivirus is deployed, as it can be exploited by attackers with minimal privileges to gain elevated system access. The privilege escalation aspect of this vulnerability aligns with common attack patterns documented in the attack mitigation framework, where adversaries leverage software flaws to move laterally within networks or establish persistent access. The potential for denial of service operations further compounds the impact, as it can disrupt legitimate antivirus functionality and create window of opportunity for additional attacks.
The vulnerability demonstrates characteristics consistent with CWE-59 symbolic link following in privileged code, where a program follows symbolic links without sufficient validation to ensure the link points to an intended target. This weakness directly enables the attack vectors that lead to privilege escalation and denial of service conditions. Security professionals should note that this vulnerability represents a classic example of inadequate input validation in security software, where the protective mechanisms fail to properly sanitize user-controlled data inputs.
Organizations should immediately implement mitigation strategies including patching affected Avira Antivirus installations to version 5.0.2003.1821 or later, which addresses the symlink validation issues. Additionally, system administrators should consider implementing additional security controls such as monitoring for suspicious symlink creation patterns and restricting write permissions to critical system directories. The remediation process should also include reviewing current antivirus configuration settings to ensure that symbolic link handling is properly restricted and that the software operates with minimal necessary privileges. This vulnerability serves as a reminder of the critical importance of proper input validation and privilege separation in security software implementations.