CVE-2014-9403 in ZNC
Summary
by MITRE
The CWebAdminMod::ChanPage function in modules/webadmin.cpp in ZNC before 1.4 allows remote authenticated users to cause a denial of service (NULL pointer dereference and crash) by adding a channel with the same name as an existing channel but without the leading # character, related to a "use-after-delete" error.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 12/08/2024
The vulnerability identified as CVE-2014-9403 affects the ZNC IRC bouncer software version 1.4 and earlier, specifically within the CWebAdminMod::ChanPage function located in modules/webadmin.cpp. This issue represents a critical security flaw that enables authenticated remote attackers to execute a denial of service attack against the system. The vulnerability stems from improper handling of channel names during the web administration interface operations, creating a scenario where a malicious user can manipulate the software's internal state to trigger a crash.
The technical root cause of this vulnerability lies in a use-after-delete error pattern that manifests as a NULL pointer dereference within the web administration module. When an authenticated user attempts to add a channel with a name that matches an existing channel but lacks the required leading # character, the software's internal data structures become corrupted. This condition occurs because the system fails to properly validate channel names before processing them, leading to a situation where memory that has been freed is subsequently accessed. The flaw is particularly insidious because it requires only authenticated access, making it exploitable by users who have legitimate credentials to the ZNC server.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be leveraged to systematically crash the ZNC server and render it unavailable to legitimate users. This denial of service condition affects the entire web administration interface and potentially impacts the broader IRC communication capabilities of the server. Attackers can repeatedly exploit this vulnerability to maintain persistent service disruption, making it particularly dangerous in environments where continuous availability is critical for communication infrastructure. The vulnerability affects systems where ZNC serves as a core communication hub, potentially impacting organizations that rely on IRC-based communication channels for operational coordination.
Mitigation strategies for this vulnerability include immediate upgrading to ZNC version 1.4 or later, where the issue has been resolved through proper input validation and memory management practices. Organizations should also implement monitoring for suspicious administrative activities that might indicate exploitation attempts, particularly around channel management operations. The fix addresses the underlying use-after-delete vulnerability by ensuring proper validation of channel names and preventing access to freed memory locations. This remediation aligns with best practices for memory safety and follows the CWE-416 principle of preventing use after free conditions. Security teams should also consider implementing access controls and audit logging for administrative functions to detect and prevent unauthorized exploitation attempts, as this vulnerability operates within the context of authenticated user sessions and can be exploited through legitimate administrative interfaces.