CVE-2023-50784 in UnrealIRCd
Summary
by MITRE • 12/17/2023
A buffer overflow in websockets in UnrealIRCd 6.1.0 through 6.1.3 before 6.1.4 allows an unauthenticated remote attacker to crash the server by sending an oversized packet (if a websocket port is open). Remote code execution might be possible on some uncommon, older platforms.
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Analysis
by VulDB Data Team • 01/11/2024
UnrealIRCd versions 6.1.0 through 6.1.3 contain a critical buffer overflow vulnerability in the websocket implementation that affects systems with open websocket ports. This vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions where insufficient validation of input data leads to memory corruption. The flaw occurs when the server receives oversized websocket packets, specifically targeting the websocket handling code that fails to properly validate packet sizes before processing them. The vulnerability is classified as a remote code execution risk under ATT&CK technique T1203, as it allows unauthenticated attackers to exploit the server without requiring prior access credentials. The buffer overflow specifically affects the websocket protocol implementation within UnrealIRCd, where data received over websocket connections is not adequately bounded before being copied into fixed-size buffers. This allows attackers to overwrite adjacent memory locations and potentially redirect program execution flow.
The operational impact of this vulnerability extends beyond simple service disruption, as the buffer overflow can lead to complete server crashes and in some cases, arbitrary code execution on vulnerable systems. When an attacker sends an oversized websocket packet to a server with open websocket ports, the server's memory management fails to handle the excessive data properly, causing the program to terminate unexpectedly or potentially execute malicious code if the overflow occurs in a way that allows code injection. The vulnerability affects a specific range of UnrealIRCd versions, making it particularly dangerous for organizations that have not yet updated to version 6.1.4 or later. The fact that remote code execution is possible on older, uncommon platforms indicates that this vulnerability may be exploitable on systems with different memory layouts or compiler settings that make memory corruption more predictable and controllable. This makes the attack surface potentially larger than initially apparent, as even systems that would normally be considered secure may be vulnerable due to platform-specific memory management characteristics.
Mitigation strategies for this vulnerability should focus on immediate version updates to UnrealIRCd 6.1.4 or later, which contains the necessary patches to prevent the buffer overflow condition. Organizations should also implement network segmentation to restrict access to websocket ports, as the vulnerability requires an open websocket port to be exploitable. Network monitoring should be enhanced to detect unusual websocket traffic patterns that might indicate exploitation attempts, with particular attention to oversized packets being sent to websocket endpoints. Security teams should also consider implementing rate limiting and connection throttling mechanisms to prevent rapid exploitation attempts. The vulnerability demonstrates the importance of input validation and proper memory management in network services, as highlighted by CWE-122 which addresses heap-based buffer overflows and similar memory corruption issues. Additionally, organizations should review their websocket configurations to ensure that only necessary ports are exposed and that appropriate access controls are implemented to minimize the attack surface. System administrators should also monitor for any signs of exploitation attempts and maintain up-to-date security patches across all network infrastructure components to prevent similar vulnerabilities from being exploited in the future.