CVE-2017-10965 in irssi
Summary
by MITRE
An issue was discovered in Irssi before 1.0.4. When receiving messages with invalid time stamps, Irssi would try to dereference a NULL pointer.
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Analysis
by VulDB Data Team • 12/12/2022
The vulnerability identified as CVE-2017-10965 represents a critical null pointer dereference flaw in Irssi versions prior to 1.0.4, a widely used terminal-based IRC client. This issue arises from inadequate input validation mechanisms within the application's message processing pipeline, specifically when handling malformed timestamp data. The flaw exists in the client's ability to parse and process incoming IRC messages that contain invalid or corrupted timestamp information, creating a scenario where the software attempts to access memory through a null reference. Such behavior constitutes a fundamental violation of memory safety principles and represents a classic example of improper error handling in network communication applications.
The technical nature of this vulnerability places it squarely within CWE-476, which defines null pointer dereference as a condition where a null value is used as a pointer reference. When Irssi encounters a message with invalid timestamps, the application fails to properly validate the timestamp data structure before attempting to process it, leading to the dereferencing of a null pointer. This type of error typically results in application crashes or, in more sophisticated exploitation scenarios, could potentially allow for remote code execution if combined with other vulnerabilities. The flaw demonstrates poor defensive programming practices where the software assumes certain data structures will always contain valid references without proper null checks.
Operationally, this vulnerability poses significant risks to users who rely on Irssi for secure communications, particularly in environments where network traffic may be manipulated by adversaries. The null pointer dereference could be exploited to cause denial of service attacks against IRC clients, disrupting communication channels and potentially affecting collaborative work environments or security monitoring systems that depend on IRC for alerting and coordination. Attackers could craft malicious IRC messages with malformed timestamps to trigger the vulnerability, causing the client application to crash and potentially leading to service disruption. This represents a medium to high severity threat in security contexts where availability of communication channels is critical.
Mitigation strategies for this vulnerability require immediate patching of Irssi installations to version 1.0.4 or later, which contains the necessary fixes for proper timestamp validation. System administrators should implement network monitoring to detect and filter malformed IRC traffic that could exploit this vulnerability. The fix typically involves adding proper null pointer checks before accessing timestamp data structures and implementing robust input validation for all network-received data. Additionally, organizations should consider implementing network segmentation and access controls to limit exposure to potentially malicious IRC traffic, while also ensuring that all IRC client installations are kept up to date with security patches. This vulnerability highlights the importance of proper error handling and defensive programming techniques in network applications, particularly those handling untrusted input from remote sources.