CVE-2017-15524 in Load Balancer
Summary
by MITRE
The Application Firewall Pack (AFP, aka Web Application Firewall) component on Kemp Load Balancer devices with software before 7.2.40.1 allows a Security Feature Bypass via an HTTP POST request.
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Analysis
by VulDB Data Team • 12/16/2019
The vulnerability identified as CVE-2017-15524 affects the Application Firewall Pack component within Kemp Load Balancer devices, representing a critical security weakness that undermines the intended protection mechanisms of web application firewalls. This flaw exists in software versions prior to 7.2.40.1 and specifically targets the security feature bypass capability through crafted HTTP POST requests, potentially allowing unauthorized access to protected web applications.
The technical implementation of this vulnerability stems from insufficient validation and filtering mechanisms within the AFP component's request processing logic. When the system receives an HTTP POST request, the security controls fail to properly evaluate the request content against established security policies, enabling attackers to bypass the intended protection measures. This represents a classic case of inadequate input validation where the firewall component does not adequately distinguish between legitimate and malicious requests based on their content characteristics.
From an operational impact perspective, this vulnerability creates a significant risk exposure for organizations relying on Kemp Load Balancer devices for web application security. Attackers can exploit this bypass to circumvent the firewall's protective measures, potentially gaining unauthorized access to sensitive web applications and data. The security feature bypass allows malicious actors to perform actions that would normally be blocked by the firewall, including but not limited to data exfiltration, injection attacks, and unauthorized administrative access to protected resources.
The vulnerability aligns with CWE-284, which describes improper access control in software systems, and demonstrates how inadequate security controls can create pathways for unauthorized access. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and defense evasion, as attackers can bypass security controls while remaining undetected in the system. The bypass capability specifically relates to T1070.004, which involves bypassing security tools, and T1566, which covers spearphishing attacks that could leverage this vulnerability to gain initial access.
Organizations should implement immediate mitigations including upgrading to Kemp Load Balancer software version 7.2.40.1 or later, which contains the necessary patches to address the bypass vulnerability. Network administrators should also consider implementing additional monitoring and logging mechanisms to detect anomalous HTTP POST request patterns that might indicate exploitation attempts. The recommended approach includes conducting comprehensive security assessments of all affected devices and implementing network segmentation to limit the potential impact of successful exploitation attempts. Regular security updates and patch management procedures should be strengthened to prevent similar vulnerabilities from arising in the future, ensuring that all security components maintain current protection levels against known threats.