CVE-2015-7372 in Adserver
Summary
by MITRE
Directory traversal vulnerability in delivery-dev/al.php in Revive Adserver before 3.2.2 allows remote attackers to include and execute arbitrary local files via a .. (dot dot) in the layerstyle parameter.
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Analysis
by VulDB Data Team • 06/21/2022
The CVE-2015-7372 vulnerability represents a critical directory traversal flaw in the Revive Adserver software ecosystem, specifically within the delivery-dev/al.php component. This vulnerability exists in versions prior to 3.2.2 and fundamentally undermines the application's security by allowing remote attackers to manipulate file inclusion mechanisms through crafted input parameters. The flaw manifests when the layerstyle parameter contains .. (dot dot) sequences that enable attackers to navigate outside the intended directory structure and access arbitrary local files on the server. This directory traversal vulnerability falls under the CWE-22 category, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
The technical exploitation of this vulnerability occurs when the application fails to properly validate or sanitize user-supplied input passed through the layerstyle parameter. When an attacker submits a malicious payload containing directory traversal sequences such as ../../etc/passwd or similar constructs, the application processes these inputs without adequate sanitization, leading to unauthorized file access and potential code execution. The vulnerability leverages the fundamental weakness in input validation where the application assumes that all user input is safe and properly formatted, failing to implement proper path validation mechanisms. This weakness enables attackers to bypass intended access controls and potentially execute arbitrary code on the server, depending on the permissions and configuration of the web application.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can lead to complete system compromise when combined with other attack vectors. Attackers can leverage this vulnerability to access sensitive configuration files, database credentials, application source code, and potentially gain shell access to the underlying server. The remote nature of this attack means that an attacker does not need physical access to the system or local network privileges to exploit the vulnerability. This makes the attack surface significantly larger and more dangerous, as it can be exploited from anywhere on the internet. The vulnerability also aligns with several ATT&CK techniques including T1059 for command and script injection and T1566 for credential access through exploitation of software vulnerabilities, making it a significant concern for enterprise security posture.
Mitigation strategies for CVE-2015-7372 should focus on immediate patching of the Revive Adserver application to version 3.2.2 or later, where the vulnerability has been addressed through proper input validation and sanitization. Organizations should implement comprehensive input validation measures that reject or sanitize any input containing directory traversal sequences before processing. The application should employ proper path validation techniques that ensure all file operations occur within designated safe directories, implementing whitelisting approaches for acceptable file paths. Network-level mitigations such as web application firewalls can provide additional protection by detecting and blocking malicious patterns in incoming requests. Security monitoring should be enhanced to detect unusual file access patterns and potential exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other components of the application stack. The vulnerability also underscores the importance of following secure coding practices and implementing proper input validation as outlined in OWASP Top Ten and other security standards to prevent similar issues in future development cycles.