CVE-2007-4398 in irssi
Summary
by MITRE
Multiple CRLF injection vulnerabilities in the (1) now-playing.rb and (2) xmms.pl 1.1 scripts for weechat allow user-assisted remote attackers to execute arbitrary IRC commands via CRLF sequences in the name of the song in a .mp3 file.
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Analysis
by VulDB Data Team • 09/07/2018
The vulnerability described in CVE-2007-4398 represents a critical CRLF injection flaw affecting weechat scripting components that process media file metadata. This issue impacts two specific scripts now-playing.rb and xmms.pl 1.1 which are designed to display currently playing song information within the weechat IRC client interface. The vulnerability arises from insufficient input validation when these scripts parse and display song names from .mp3 files, creating an opportunity for remote attackers to inject malicious CRLF sequences that can be interpreted as command terminators within the IRC protocol context.
The technical implementation of this vulnerability stems from the scripts' failure to properly sanitize user-supplied data from media file tags, particularly the title field of audio files. When these scripts encounter a song name containing carriage return and line feed characters, they incorporate these sequences directly into the IRC command output without proper encoding or escaping mechanisms. This allows attackers to craft specially formatted .mp3 files with malicious CRLF sequences in their metadata that, when processed by the vulnerable scripts, result in the execution of unintended IRC commands on behalf of the target user.
From an operational perspective, this vulnerability enables man-in-the-middle attacks where remote adversaries can manipulate the IRC client's output to inject commands that appear to originate from legitimate sources. The impact extends beyond simple command injection as it can facilitate session hijacking, channel manipulation, and potentially lead to more severe compromise scenarios. Attackers can leverage this vulnerability to execute commands such as /part, /join, /msg, or other IRC commands that could disrupt communications or establish unauthorized access to chat channels, particularly when the vulnerable scripts are used in public or shared IRC environments.
The vulnerability aligns with CWE-117, which addresses improper output neutralization for logs, and maps to ATT&CK technique T1059.008 for command and scripting interpreter. The attack chain typically involves the attacker preparing a malicious .mp3 file with embedded CRLF sequences, sharing it within an IRC environment where the vulnerable weechat scripts are active, and observing the execution of unintended commands when other users view the now-playing information. Mitigation strategies should focus on implementing strict input validation and output encoding mechanisms, updating to patched versions of weechat, and potentially disabling or restricting the use of vulnerable scripts in high-risk environments. Organizations should also consider network-level monitoring for unusual IRC command patterns that could indicate exploitation attempts, while ensuring proper patch management protocols are in place to address similar vulnerabilities in other software components that handle user-supplied data within protocol contexts.