CVE-2006-0852 in Admbook
Summary
by MITRE
Direct static code injection vulnerability in write.php in Admbook 1.2.2 and earlier allows remote attackers to execute arbitrary PHP code via the X-Forwarded-For HTTP header field, which is inserted into content-data.php.
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Analysis
by VulDB Data Team • 06/16/2024
The vulnerability described in CVE-2006-0852 represents a critical direct static code injection flaw within the Admbook 1.2.2 content management system and earlier versions. This vulnerability exists in the write.php script where the application fails to properly sanitize user input from the X-Forwarded-For HTTP header field. The X-Forwarded-For header is commonly used by web proxies and load balancers to identify the original IP address of a client connecting to a web server, but in this case, the application treats it as trusted input without adequate validation or sanitization. When an attacker sends a malicious X-Forwarded-For header containing PHP code, this code gets directly injected into the content-data.php file and subsequently executed by the web server, creating a remote code execution vulnerability that can be exploited from anywhere on the internet.
The technical nature of this vulnerability aligns with CWE-94, which describes "Improper Control of Generation of Code ('Code Injection')" and specifically relates to situations where untrusted data is used to generate code without proper sanitization or validation. This flaw operates at the application layer where user-supplied data flows directly into code execution contexts without appropriate input filtering mechanisms. The vulnerability is particularly dangerous because it leverages a header field that is commonly present in HTTP requests, making it difficult to detect and block at network level. Attackers can craft malicious headers containing PHP code that gets stored and executed, effectively allowing them to gain full control over the vulnerable web server and potentially compromise the entire hosting environment.
From an operational perspective, this vulnerability creates a severe risk for any organization using Admbook 1.2.2 or earlier versions, as it enables remote attackers to execute arbitrary commands on the target system with the privileges of the web server process. The impact extends beyond simple code execution to include potential data theft, system compromise, and further lateral movement within the network. The vulnerability is particularly concerning because it can be exploited through a simple HTTP request containing a malicious X-Forwarded-For header, making it easily automatable and scalable for mass exploitation. According to ATT&CK framework, this vulnerability maps to T1059.007 for "Command and Scripting Interpreter: PowerShell" and T1078.004 for "Valid Accounts: Cloud Accounts" when considering the potential for privilege escalation and account compromise. The attack surface is broad as any web server using Admbook and accepting requests through proxies that forward this header is potentially vulnerable.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security architecture improvements. The most effective immediate fix involves upgrading to a patched version of Admbook, as this vulnerability was resolved in later releases through proper input sanitization and validation. Organizations should implement comprehensive input validation for all HTTP headers, particularly those that are commonly used for proxy information such as X-Forwarded-For, X-Forwarded-Host, and X-Forwarded-Proto. The implementation of a web application firewall (WAF) with rules specifically designed to detect and block malicious header content can provide additional protection layers. Additionally, organizations should implement proper output encoding and context-aware sanitization for all user-supplied data that enters the application. The principle of least privilege should be enforced by running web applications with minimal necessary permissions, and regular security audits should be conducted to identify similar vulnerabilities in other applications. Network segmentation and monitoring solutions should be deployed to detect unusual patterns in HTTP header usage that might indicate exploitation attempts.