CVE-2015-8357 in xscan Module
Summary
by MITRE
Directory traversal vulnerability in the bitrix.xscan module before 1.0.4 for Bitrix allows remote authenticated users to rename arbitrary files, and consequently obtain sensitive information or cause a denial of service, via a .. (dot dot) in the file parameter to admin/bitrix.xscan_worker.php.
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Analysis
by VulDB Data Team • 01/12/2025
The CVE-2015-8357 vulnerability represents a critical directory traversal flaw within the bitrix.xscan module of Bitrix CMS systems. This vulnerability affects versions prior to 1.0.4 and exposes a significant security weakness that allows authenticated attackers to manipulate file operations through crafted input parameters. The vulnerability specifically manifests in the admin/bitrix.xscan_worker.php endpoint where the file parameter fails to properly validate or sanitize user-supplied input containing directory traversal sequences.
The technical exploitation of this vulnerability leverages the .. (dot dot) sequence to traverse directory structures and manipulate file operations. When an authenticated user submits a malicious file parameter containing directory traversal sequences to the vulnerable endpoint, the system processes these requests without adequate validation, allowing attackers to rename arbitrary files within the application's file system. This fundamental flaw in input validation creates a pathway for attackers to access sensitive system files, potentially leading to information disclosure or system compromise. The vulnerability operates at the application level where proper path validation mechanisms are absent or insufficient.
From an operational impact perspective, this vulnerability enables authenticated attackers to execute arbitrary file renaming operations that can have severe consequences for system integrity and security. The ability to rename arbitrary files opens doors to information disclosure attacks where sensitive configuration files, database credentials, or application source code could be accessed through file renaming operations. Additionally, attackers can potentially cause denial of service conditions by renaming critical system files or directories, rendering the application unstable or completely non-functional. The authenticated nature of the vulnerability means that attackers must first establish valid credentials, but once obtained, they can leverage this flaw to escalate their privileges and compromise the entire system.
The vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. This classification emphasizes the fundamental flaw in how the application handles file paths and validates user input. From an adversarial perspective, this vulnerability maps to multiple ATT&CK techniques including T1059 for command and scripting interpreter and T1078 for valid accounts, as attackers would need legitimate credentials to exploit the vulnerability while potentially using it to establish persistence or escalate privileges. The attack chain typically involves initial access through valid credentials followed by exploitation of the directory traversal vulnerability to gain unauthorized file system access.
Mitigation strategies for CVE-2015-8357 require immediate patching of the affected bitrix.xscan module to version 1.0.4 or later where the directory traversal vulnerability has been addressed. Organizations should implement comprehensive input validation measures that sanitize all user-supplied parameters, particularly those used in file operations, to prevent the injection of directory traversal sequences. Network segmentation and access controls should be enforced to limit the scope of potential exploitation, ensuring that only authorized users can access the vulnerable administrative endpoints. Regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other components of the Bitrix CMS system, while implementing proper logging and monitoring mechanisms to detect suspicious file operations that may indicate exploitation attempts.