CVE-2007-3580 in PHPIDS
Summary
by MITRE
PHPIDS does not properly handle certain code containing newlines, as demonstrated by a try/catch block within a loop, which allows user-assisted remote attackers to inject arbitrary web script.
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Analysis
by VulDB Data Team • 10/25/2017
The vulnerability identified as CVE-2007-3580 affects PHPIDS (PHP Intrusion Detection System), a security tool designed to detect and prevent various types of web application attacks including cross-site scripting and SQL injection attempts. This particular flaw represents a critical weakness in the system's input validation and sanitization mechanisms, specifically when processing code structures containing newline characters. The vulnerability stems from PHPIDS's inadequate handling of code constructs that include try/catch blocks nested within loops, where newlines are present in unexpected positions within the code structure. This improper handling creates a condition where malicious actors can craft specially formatted input that bypasses the intrusion detection system's normal validation procedures. The flaw operates at the core level of how PHPIDS processes and analyzes code patterns, fundamentally undermining its ability to identify potentially malicious code sequences that contain legitimate programming constructs with embedded newlines.
The technical implementation of this vulnerability exploits the way PHPIDS parses and evaluates code patterns for potential threats. When encountering code structures with try/catch blocks within loops, the system fails to properly normalize or sanitize the input before analysis, allowing newlines to interfere with the detection algorithms. This creates a path where attackers can inject arbitrary web scripts that appear benign to the detection system but contain malicious payload elements. The vulnerability specifically targets the code analysis engine's inability to properly handle multi-line code structures, where the newline characters disrupt the expected parsing flow. The flaw is particularly dangerous because it allows attackers to craft inputs that would normally be detected by PHPIDS but are instead passed through undetected due to the improper handling of newline characters in code constructs. This represents a classic case of improper input validation where the system fails to account for legitimate programming constructs that contain newline characters, creating an unexpected bypass mechanism.
The operational impact of this vulnerability extends far beyond simple bypass of security measures, as it fundamentally compromises the integrity of the PHPIDS protection framework. An attacker who successfully exploits this vulnerability can execute arbitrary web scripts on systems protected by PHPIDS, potentially leading to complete system compromise, data exfiltration, or further lateral movement within the network. The vulnerability affects any web application that relies on PHPIDS for security protection, making it particularly dangerous in environments where multiple applications share the same intrusion detection infrastructure. Organizations using PHPIDS may experience false security assurances while remaining vulnerable to sophisticated attacks that exploit this specific parsing weakness. The vulnerability's impact is amplified by the fact that it can be triggered through user-assisted remote attacks, meaning that malicious actors can leverage legitimate user interactions to deliver the exploit, making detection and prevention significantly more challenging. This flaw essentially creates a backdoor within the security system itself, allowing attackers to inject malicious code that bypasses the very mechanisms designed to prevent such attacks.
Mitigation strategies for this vulnerability require immediate attention and multiple layers of protection to address the root cause and prevent exploitation. The primary recommendation involves updating to a patched version of PHPIDS that properly handles newline characters in code constructs, specifically addressing the try/catch within loop scenarios. Organizations should implement additional input validation measures at multiple layers of their application architecture, including server-side validation and client-side sanitization, to provide defense in depth. Network-based intrusion detection systems should be configured to monitor for unusual code injection patterns that might indicate exploitation attempts, even when PHPIDS fails to detect them. Security teams should also consider implementing runtime application self-protection mechanisms that can detect and block suspicious code execution patterns regardless of the IDS system's performance. The vulnerability aligns with CWE-20, which addresses improper input validation, and maps to ATT&CK technique T1059.007 for execution through web shells and script injection. Regular security assessments and penetration testing should be conducted to identify similar weaknesses in other security tools and applications that might exhibit similar parsing vulnerabilities. Organizations should also implement comprehensive logging and monitoring to detect potential exploitation attempts and maintain detailed audit trails of security events for forensic analysis purposes.