CVE-2009-4023 in PEAR
Summary
by MITRE
Argument injection vulnerability in the sendmail implementation of the Mail::Send method (Mail/sendmail.php) in the Mail package 1.1.14 for PEAR allows remote attackers to read and write arbitrary files via a crafted $from parameter, a different vector than CVE-2009-4111.
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Analysis
by VulDB Data Team • 08/28/2021
The CVE-2009-4023 vulnerability represents a critical argument injection flaw within the Mail::Send method implementation of the PEAR Mail package version 1.1.14. This vulnerability specifically affects the sendmail transport mechanism where the $from parameter is improperly handled, creating a pathway for remote attackers to execute arbitrary file operations. The flaw exists in the Mail/sendmail.php file and demonstrates a classic example of insecure input handling that can be exploited to manipulate the underlying sendmail command execution process.
The technical exploitation of this vulnerability occurs when the Mail::Send method processes a crafted $from parameter that contains malicious command injection sequences. The vulnerability stems from insufficient sanitization of user-supplied input before it is passed to the sendmail command, which operates with elevated privileges and can execute arbitrary file read and write operations. Attackers can leverage this weakness to bypass normal access controls and gain unauthorized access to the file system, potentially leading to data exfiltration, system compromise, or further attack escalation. This vulnerability operates through a distinct attack vector compared to CVE-2009-4111, making it particularly concerning as it provides an additional pathway for exploitation.
The operational impact of CVE-2009-4023 extends beyond simple file access violations to encompass broader system compromise potential. When exploited, this vulnerability allows attackers to perform arbitrary file operations including reading sensitive configuration files, writing malicious code to system directories, or accessing database credentials stored in plain text files. The vulnerability affects web applications that utilize the PEAR Mail package for email functionality, particularly those that accept user input for email addresses or sender information without proper validation. This creates a significant risk for web applications handling sensitive data or operating in multi-tenant environments where privilege escalation could lead to unauthorized access to other users' data or system resources.
Mitigation strategies for this vulnerability require immediate patching of the affected PEAR Mail package to version 1.1.15 or later, which contains the necessary input sanitization fixes. Organizations should implement comprehensive input validation for all email-related parameters, particularly those used in the $from field, and employ proper escaping mechanisms before passing user data to system commands. The vulnerability aligns with CWE-77 and CWE-78 categories, representing command injection flaws that can be exploited through improper input handling. Additionally, implementing proper privilege separation, using sandboxed execution environments for email operations, and regularly monitoring system logs for suspicious command execution patterns can help detect and prevent exploitation attempts. Security teams should also consider implementing network-based intrusion detection systems that can identify patterns consistent with command injection attacks targeting the sendmail transport mechanism.
The attack surface for this vulnerability is particularly wide given the widespread adoption of the PEAR Mail package across various web applications and content management systems. The vulnerability demonstrates the critical importance of proper input validation in applications that interface with system-level commands and highlights the potential for seemingly benign functionality to become a gateway for serious security breaches. Organizations should conduct thorough vulnerability assessments to identify all instances of the affected Mail package and ensure that proper security controls are in place to prevent similar issues in other components of their web applications. This vulnerability also underscores the necessity of maintaining up-to-date security patches and implementing robust security monitoring to detect and respond to exploitation attempts before they can cause significant damage to the system or data integrity.