CVE-2018-7053 in irssi
Summary
by MITRE
An issue was discovered in Irssi before 1.0.7 and 1.1.x before 1.1.1. There is a use-after-free when SASL messages are received in an unexpected order.
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Analysis
by VulDB Data Team • 02/08/2023
The vulnerability identified as CVE-2018-7053 represents a critical use-after-free condition affecting the Irssi IRC client software across multiple version ranges. This flaw manifests specifically when the application processes Simple Authentication and Security Layer messages that arrive in an unexpected sequence during the authentication process. The Irssi client, widely used for IRC communication, implements SASL authentication to verify user identities and establish secure connections to IRC servers. The vulnerability arises from inadequate memory management within the SASL processing module, where the application fails to properly handle message ordering and subsequent memory deallocation. When SASL messages are received out of sequence, the software attempts to access memory that has already been freed, creating a dangerous state that can be exploited by remote attackers.
The technical nature of this vulnerability aligns with CWE-416, which defines use-after-free conditions as a class of memory safety issues where program code continues to reference memory after it has been freed. This particular implementation flaw occurs within the SASL authentication handling code path of Irssi, where the application maintains references to memory structures containing SASL message data. When the authentication sequence is disrupted through unexpected message ordering, the software's memory management logic does not properly validate whether referenced memory regions remain valid. The vulnerability demonstrates characteristics consistent with memory corruption issues that can lead to arbitrary code execution, making it particularly dangerous in networked environments where attackers can control message flow. The flaw exists in both the 1.0.x branch prior to version 1.0.7 and the 1.1.x branch prior to version 1.1.1, indicating this was a persistent issue in the codebase.
The operational impact of CVE-2018-7053 extends beyond simple application instability to potentially enable remote code execution capabilities for malicious actors. Attackers can exploit this vulnerability by crafting specially formatted SASL messages that arrive in unexpected order, triggering the use-after-free condition during the authentication handshake process. This attack vector is particularly concerning because it can be executed remotely without requiring authentication, as the vulnerability occurs during the connection establishment phase. The consequences include potential system compromise, data exfiltration, and unauthorized access to IRC networks. Organizations relying on Irssi for secure communications face significant risk, as the vulnerability can be leveraged to gain control over client systems or intercept sensitive communications. The vulnerability's presence in widely deployed versions means that numerous installations across different network environments could be at risk, making it a high-priority issue for security teams.
Mitigation strategies for CVE-2018-7053 primarily focus on immediate software updates and operational security measures. The most effective solution involves upgrading to Irssi versions 1.0.7 or 1.1.1 and later, which contain patches addressing the memory management issues in the SASL processing code. System administrators should prioritize patching affected installations, particularly those handling sensitive communications or operating in hostile network environments. Additional defensive measures include implementing network monitoring to detect anomalous SASL message sequences and configuring firewalls to restrict IRC traffic where possible. Organizations should also consider implementing intrusion detection systems that can identify potential exploitation attempts targeting this specific vulnerability. The fix implemented in patched versions addresses the core memory management flaw by ensuring proper validation of message ordering and memory state before access operations, thereby preventing the use-after-free condition from occurring during authentication sequences. Security teams should also conduct vulnerability assessments to identify all affected Irssi installations within their network infrastructure and establish monitoring procedures to detect potential exploitation attempts.