Source: cve@mitre.org
Buffer overflow in BNC IRC proxy allows remote attackers to gain privileges.
BNC IRC proxy software is vulnerable to a buffer overflow, allowing remote attackers to potentially execute arbitrary code and gain unauthorized access to the system. Exploiting this vulnerability could lead to complete system compromise, including data theft and denial of service. This is a critical vulnerability that requires immediate attention.
Step 1: Payload Delivery: The attacker connects to the vulnerable BNC IRC proxy server.
Step 2: Crafted Input: The attacker sends a specially crafted IRC command or data, such as a long nickname or message, designed to overflow a buffer within the BNC proxy.
Step 3: Buffer Overflow: The proxy, failing to validate the input size, writes the oversized data into a fixed-size buffer, overwriting adjacent memory locations.
Step 4: Control Hijack: The attacker's crafted input overwrites the return address on the stack or other critical program data.
Step 5: Code Execution: When the vulnerable function returns, control is transferred to the attacker-controlled memory location, executing the attacker's payload (e.g., shellcode) and granting them privileges.
The vulnerability lies within the BNC IRC proxy's handling of user-supplied input. Specifically, the proxy fails to properly validate the size of data received from a client before writing it to a fixed-size buffer. This lack of bounds checking allows an attacker to send a specially crafted input that exceeds the buffer's capacity, leading to a buffer overflow. This overwrites adjacent memory regions, potentially including critical program data or control flow information. By carefully crafting the overflow, an attacker can overwrite the return address on the stack, redirecting program execution to malicious code (e.g., a shellcode payload) they control. The root cause is a missing or inadequate input validation mechanism, allowing for the overflow to occur. The specific function or logic flaw is likely related to how the proxy handles client commands or data, such as the handling of nicknames, channel names, or messages, without proper size checks.
Due to the age of the vulnerability, it's difficult to definitively link it to specific APT groups. However, any threat actor seeking to gain initial access or escalate privileges would find this vulnerability valuable. The vulnerability's impact (remote code execution) makes it a high-priority target. CISA KEV status: Unknown, but likely not listed due to its age and the focus on more recent vulnerabilities. However, the potential impact warrants consideration.
Network traffic analysis: Look for unusually long IRC commands or data packets sent to the BNC proxy.
Log analysis: Examine BNC proxy logs for suspicious activity, such as errors related to buffer overflows or unexpected program behavior.
Host-based intrusion detection systems (HIDS): Monitor for changes in system files, suspicious process creation, or unauthorized network connections originating from the BNC proxy server.
Memory forensics: Analyze memory dumps of the BNC proxy process for evidence of buffer overflows or malicious code injection.
Signature-based detection: Implement signatures in intrusion detection/prevention systems (IDS/IPS) to identify known exploit attempts.
File integrity monitoring: Monitor critical BNC proxy files for unauthorized modifications.
Upgrade to the latest version of the BNC IRC proxy software or a patched version that addresses the buffer overflow vulnerability.
If upgrading is not possible, consider disabling the BNC proxy service if it is not essential.
Implement input validation to ensure that all user-supplied data is properly sanitized and validated before being processed by the BNC proxy.
Apply security patches promptly as they become available.
Implement a strong network segmentation strategy to limit the impact of a successful exploit.
Regularly audit and review system configurations to ensure they are secure.
Implement a web application firewall (WAF) to filter malicious traffic.