CVE-2006-2550 in perlpodder
Summary
by MITRE
perlpodder before 0.5 allows remote attackers to execute arbitrary code via shell metacharacters in the URL of a podcast, which are executed when saving the URL to a log file. NOTE: the wget vector is already covered by CVE-2006-2548.
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Analysis
by VulDB Data Team • 07/27/2018
The vulnerability described in CVE-2006-2550 affects perlpodder version 0.5 and earlier, representing a critical remote code execution flaw that exploits improper input validation in podcast URL handling. This vulnerability specifically targets the application's logging mechanism where podcast URLs are stored without adequate sanitization, creating an avenue for attackers to inject malicious shell metacharacters that get executed during the logging process. The flaw demonstrates a classic command injection vulnerability where user-controllable input directly influences shell command execution, making it particularly dangerous in networked environments where podcast feeds are processed automatically.
The technical implementation of this vulnerability stems from the application's failure to properly escape or filter special shell characters within podcast URLs before they are written to log files. When perlpodder processes a podcast feed and encounters a URL containing metacharacters such as semicolons, ampersands, or backticks, these characters are not properly sanitized before being logged. The application then executes shell commands to save the URL to its logging mechanism, inadvertently executing the malicious payload embedded within the URL. This type of vulnerability is classified as a command injection flaw under CWE-77 and represents a significant weakness in input validation and output encoding practices. The attack vector is particularly insidious because it requires no direct interaction with the application's user interface, making it susceptible to exploitation through automated means.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with full control over the system running perlpodder. The remote code execution capability allows adversaries to perform arbitrary operations including but not limited to data exfiltration, system reconnaissance, privilege escalation, and persistence establishment. Attackers could potentially use this vulnerability to install backdoors, modify system configurations, or compromise other network resources accessible from the affected system. The vulnerability's exploitation does not require authentication or specific user interaction, making it particularly attractive to threat actors seeking to compromise systems automatically. This aligns with ATT&CK technique T1059.001 for command and scripting interpreter, specifically shell scripting, and represents a common pathway for attackers to establish persistent access to compromised systems.
The mitigation strategy for this vulnerability involves immediate patching of perlpodder to version 0.5 or later, which contains proper input sanitization and output escaping mechanisms. Organizations should implement comprehensive input validation that filters or escapes shell metacharacters before any user-controllable data is processed or logged. The solution should include proper escaping of special characters in shell contexts and the implementation of secure coding practices that prevent command injection vulnerabilities. Additionally, network segmentation and access controls should be implemented to limit the potential impact of exploitation, while monitoring systems should be configured to detect unusual logging patterns or command execution attempts. Security teams should also consider implementing web application firewalls and input validation rules to prevent malicious URLs from being processed by the application. The vulnerability's classification under CWE-77 and its exploitation pattern align with standard remediation approaches for command injection flaws, emphasizing the importance of proper input sanitization and secure coding practices throughout the application development lifecycle.