CVE-2017-14500 in newsbeuter
Summary
by MITRE
Improper Neutralization of Special Elements used in an OS Command in the podcast playback function of Podbeuter in Newsbeuter 0.3 through 2.9 allows remote attackers to perform user-assisted code execution by crafting an RSS item with a media enclosure (i.e., a podcast file) that includes shell metacharacters in its filename, related to pb_controller.cpp and queueloader.cpp, a different vulnerability than CVE-2017-12904.
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Analysis
by VulDB Data Team • 12/29/2022
This vulnerability exists within the podcast playback functionality of Newsbeuter version 0.3 through 2.9, specifically in the Podbeuter component that handles media enclosure processing. The flaw stems from inadequate input sanitization when processing RSS feed items containing podcast files with specially crafted filenames. When a malicious actor crafts an RSS item with a media enclosure that includes shell metacharacters in its filename, the application fails to properly neutralize these special elements before executing OS commands. This represents a classic command injection vulnerability that operates through the podcast playback mechanism rather than direct user input processing.
The technical implementation of this vulnerability occurs in two primary files: pb_controller.cpp and queueloader.cpp, which handle the controller logic and queue loading operations respectively. When Newsbeuter processes an RSS feed containing a malicious podcast enclosure, the application constructs OS commands using the filename without proper sanitization or escaping of shell metacharacters. This allows attackers to inject arbitrary shell commands that get executed with the privileges of the user running Newsbeuter. The vulnerability is particularly concerning because it requires only a single user-assisted action to trigger, meaning a user must simply open a malicious RSS feed item containing the crafted podcast filename to be exploited. This attack vector aligns with CWE-78, which specifically addresses improper neutralization of special elements used in OS commands, and demonstrates the dangerous intersection of feed parsing and command execution.
The operational impact of this vulnerability extends beyond simple code execution to potentially compromise the entire user system. Since the exploitation requires only user-assisted interaction through opening a malicious RSS feed item, attackers can leverage social engineering tactics to deliver payloads through seemingly legitimate news sources or podcast directories. The vulnerability affects a wide range of users who rely on Newsbeuter for RSS feed consumption, particularly those who frequently download and play podcasts through the application. Attackers could potentially execute commands such as system reconnaissance, data exfiltration, or even establish persistent backdoors on the victim's system. The attack surface is further expanded by the fact that many RSS feeds and podcast directories are publicly accessible, making this vulnerability particularly dangerous in environments where users regularly consume feeds from untrusted sources.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and sanitization mechanisms within the podcast playback functionality. The most effective approach involves escaping or removing shell metacharacters from filenames before constructing OS commands, ensuring that user-supplied data cannot be interpreted as shell commands. Additionally, implementing a whitelist-based approach for filename validation and employing proper command execution techniques such as using parameterized commands instead of string concatenation would significantly reduce the risk. Users should be encouraged to update to versions of Newsbeuter that have addressed this vulnerability, while system administrators should consider implementing network-level filtering to prevent access to potentially malicious RSS feeds. This vulnerability also highlights the importance of secure coding practices in applications that process external data feeds, particularly those that execute system commands based on user-provided input. The ATT&CK framework categorizes this as a command injection technique, and organizations should consider implementing defensive measures such as input validation controls and privilege separation to reduce the attack surface and impact of similar vulnerabilities.