CVE-2015-5662 in Avast!
Summary
by MITRE
Directory traversal vulnerability in Avast before 150918-0 allows remote attackers to delete or write to arbitrary files via a crafted entry in a ZIP archive.
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Analysis
by VulDB Data Team • 06/22/2022
The vulnerability identified as CVE-2015-5662 represents a critical directory traversal flaw within Avast antivirus software versions prior to 150918-0. This weakness resides in the software's handling of ZIP archive entries and enables remote attackers to execute unauthorized file operations on affected systems. The vulnerability stems from inadequate input validation and path resolution mechanisms when processing compressed archive contents, creating a pathway for malicious actors to manipulate file system access controls and potentially compromise system integrity.
This directory traversal vulnerability operates through the manipulation of file paths within ZIP archive entries, specifically targeting how Avast processes relative path references such as ../ or ..\ sequences. When the antivirus software extracts files from maliciously crafted archives, it fails to properly sanitize or validate the extracted file paths, allowing attackers to specify arbitrary locations on the target system for file creation or deletion operations. The flaw essentially permits attackers to bypass normal file system access controls and execute operations outside of intended directories, making it particularly dangerous in enterprise environments where antivirus software typically runs with elevated privileges.
The operational impact of CVE-2015-5662 extends beyond simple file manipulation to potentially enable complete system compromise. Remote attackers could leverage this vulnerability to delete critical system files, overwrite configuration data, or create malicious files in system directories, potentially leading to privilege escalation or persistent access. The vulnerability affects systems where Avast is deployed as an endpoint protection solution, particularly in environments where users might be tricked into opening maliciously crafted ZIP files through social engineering or phishing campaigns. Given that antivirus software often runs with administrative privileges, successful exploitation could result in complete system compromise without requiring additional attack vectors.
The technical implementation of this vulnerability aligns with common directory traversal patterns documented in CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal. This classification indicates that the vulnerability represents a fundamental flaw in input validation and path resolution processes within the software's archive handling functionality. From an attack framework perspective, this vulnerability maps to multiple ATT&CK techniques including T1059 for execution through malicious file manipulation and T1070 for file deletion or modification activities. The vulnerability demonstrates how seemingly benign file processing operations can become attack vectors when proper security controls are not implemented in the codebase.
Mitigation strategies for CVE-2015-5662 primarily involve upgrading to Avast version 150918-0 or later, which includes proper input validation and path sanitization measures. Organizations should implement comprehensive patch management procedures to ensure all endpoint protection software remains current with security updates. Additional defensive measures include restricting user privileges when processing untrusted archives, implementing network-based restrictions on file transfers, and deploying additional security controls such as application whitelisting to prevent execution of maliciously crafted archive files. Security monitoring should focus on detecting unusual file system operations and unauthorized access patterns that might indicate exploitation attempts. Regular security assessments of endpoint protection software configurations and proper input validation controls should be conducted to prevent similar vulnerabilities from emerging in other security software components.