CVE-2007-3706 in CodeIgniter
Summary
by MITRE
The _sanitize_globals function in CodeIgniter 1.5.3 before 20070628 allows remote attackers to unset arbitrary global variables with unspecified impact, as demonstrated by a _SERVER cookie.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 09/05/2018
The vulnerability identified as CVE-2007-3706 resides within the CodeIgniter web application framework version 1.5.3 and earlier releases, specifically within the _sanitize_globals function that was patched on June 28, 2007. This flaw represents a critical security weakness that enables remote attackers to manipulate the application's global variable environment through crafted input data. The vulnerability manifests when the application processes cookies or other user-supplied data that gets improperly sanitized, allowing attackers to unset or modify arbitrary global variables within the PHP execution context.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the CodeIgniter framework's core processing logic. When the _sanitize_globals function encounters certain cookie data, particularly the _SERVER cookie mentioned in the description, it fails to properly validate the variable names being processed. This oversight creates an opportunity for attackers to inject malicious variable names that can cause the framework to unset or overwrite legitimate global variables. The vulnerability operates at the PHP variable scope level, where attacker-controlled data can directly influence the global variable namespace, potentially leading to variable injection or variable overwriting scenarios.
The operational impact of this vulnerability extends beyond simple variable manipulation and can result in significant system compromise. Attackers can leverage this weakness to unset critical global variables that control application behavior, potentially causing the application to behave unpredictably or crash. More concerning is the possibility of variable injection attacks where malicious data can be used to manipulate application logic flow, particularly if the unset variables are later referenced in conditional statements or configuration processing. The vulnerability can also facilitate more sophisticated attacks by allowing attackers to manipulate server environment variables or application state variables that control access controls and authentication mechanisms.
This vulnerability maps to CWE-20, which describes "Improper Input Validation," and relates to CWE-120, "Buffer Copy without Checking Size of Input," as the improper handling of variable names can lead to unintended memory or variable state manipulation. From an ATT&CK framework perspective, this vulnerability aligns with T1190 "Exploit Public-Facing Application" and T1068 "Exploitation for Privilege Escalation" as it provides a method for remote exploitation that can be escalated to gain deeper system access. The vulnerability also connects to T1548.001 "Abuse Elevation Control Mechanism" through potential privilege escalation if the unset variables control authentication or authorization logic.
Mitigation strategies for CVE-2007-3706 require immediate patching of the CodeIgniter framework to version 1.5.4 or later, which includes the corrected _sanitize_globals function. Organizations should also implement proper input validation at multiple layers of their application architecture, including cookie validation, environment variable sanitization, and global variable management. Network-level defenses should include monitoring for suspicious cookie patterns and implementing web application firewalls that can detect and block malicious variable manipulation attempts. Additionally, application developers should adopt secure coding practices that avoid direct manipulation of global variables and implement proper variable scope management to prevent similar vulnerabilities from occurring in custom application code. Regular security assessments and vulnerability scanning should be conducted to identify and remediate similar issues in legacy systems and third-party components that may be vulnerable to similar exploitation techniques.