CVE-2018-15904 in ACOS Web Application Firewall
Summary
by MITRE
A10 ACOS Web Application Firewall (WAF) 2.7.1 and 2.7.2 before 2.7.2-P12, 4.1.0 before 4.1.0-P11, 4.1.1 before 4.1.1-P8, and 4.1.2 before 4.1.2-P4 mishandles the configured rules for blocking SQL injection attacks, aka A10-2017-0008.
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Analysis
by VulDB Data Team • 03/18/2020
The vulnerability identified as CVE-2018-15904 affects A10 ACOS Web Application Firewall versions 2.7.1 and 2.7.2 prior to 2.7.2-P12, along with several 4.x series versions before their respective patches. This issue represents a critical flaw in the firewall's security rule implementation specifically targeting SQL injection attack prevention mechanisms. The vulnerability stems from improper handling of configured rules designed to block malicious SQL injection attempts, creating a significant security gap in the WAF's protective capabilities.
The technical flaw manifests in the way the A10 ACOS WAF processes and applies security rules for SQL injection detection and prevention. When administrators configure rules to block SQL injection attacks, the system fails to properly evaluate or enforce these protections, allowing malicious payloads that should have been blocked to pass through the firewall undetected. This represents a classic case of inadequate input validation and rule enforcement, where the security controls designed to prevent database injection attacks are bypassed due to flawed implementation logic within the WAF's rule processing engine.
The operational impact of this vulnerability is severe as it directly undermines the fundamental security posture of organizations relying on A10 WAF appliances for web application protection. Attackers can exploit this weakness to bypass SQL injection prevention mechanisms, potentially gaining unauthorized access to backend databases, executing arbitrary code, or extracting sensitive information from vulnerable applications. The vulnerability affects organizations using multiple A10 WAF versions across different product lines, creating widespread exposure risk for enterprises that have not yet applied the necessary security patches. This type of bypass vulnerability aligns with CWE-284 Access Control Issues, where insufficient controls allow unauthorized access to protected resources.
Organizations should immediately implement mitigations including applying the vendor-provided patches for each affected version, specifically the P12, P11, P8, and P4 releases mentioned in the vulnerability description. Network segmentation and additional monitoring controls should be deployed to detect potential exploitation attempts while patches are being applied. Security teams should also conduct thorough vulnerability assessments of all A10 WAF deployments to identify systems requiring immediate remediation. The ATT&CK framework categorizes this vulnerability under T1071.004 Application Layer Protocol: DNS and T1190 Exploit Public-Facing Application, as it represents a weakness in application security controls that allows for exploitation of web application vulnerabilities. Additionally, this vulnerability demonstrates characteristics of T1210 Exploitation of Remote Services, where the WAF's own security controls are compromised to allow malicious activity to proceed undetected.