Source: cve@mitre.org
Buffer overflow in Lotus Domino web server before R5.0.10, when logging to DOMLOG.NSF, allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a long HTTP Authenticate header containing certain non-ASCII characters.
Lotus Domino web servers are vulnerable to a remote buffer overflow, allowing attackers to crash the server and potentially execute arbitrary code. Exploitation involves sending a specially crafted HTTP request with a long, non-ASCII character-containing Authenticate header, leading to a denial-of-service or complete system compromise. This vulnerability, dating back to 2002, highlights the importance of patching legacy systems and robust input validation.
Step 1: Payload Delivery: The attacker crafts an HTTP request targeting the vulnerable Lotus Domino web server. The request includes a malicious Authenticate header. This header is designed to be excessively long and contain specific non-ASCII characters, which are crucial for triggering the overflow.
Step 2: Request Processing: The Domino web server receives the crafted HTTP request. It parses the request, including the Authenticate header.
Step 3: Logging to DOMLOG.NSF: The server attempts to log the Authenticate header to the DOMLOG.NSF database. This logging process is where the vulnerability lies.
Step 4: Buffer Overflow: The server copies the contents of the Authenticate header into a fixed-size buffer within the logging function. Due to the lack of proper bounds checking, the excessively long header overflows the buffer, overwriting adjacent memory.
Step 5: Denial of Service/Code Execution: The buffer overflow corrupts critical data structures, leading to a crash (denial of service). In some cases, with careful crafting of the malicious header, the attacker can overwrite code pointers and redirect execution to arbitrary code of their choosing, achieving remote code execution.
The vulnerability stems from a buffer overflow in the Lotus Domino web server's handling of the HTTP Authenticate header when logging to DOMLOG.NSF. Specifically, the server fails to properly validate the length of the Authenticate header before writing it to a fixed-size buffer. When a long header containing certain non-ASCII characters is received, it overflows the buffer, overwriting adjacent memory. This can lead to a crash (denial of service) or, with careful crafting, arbitrary code execution. The root cause is likely a missing or inadequate bounds check on the input string length before the write operation. The use of non-ASCII characters further complicates the issue, potentially leading to incorrect string length calculations and exacerbating the overflow.
While no specific APT groups are exclusively known to exploit this vulnerability, it is a prime target for opportunistic attackers and those seeking initial access. Given its age and the availability of exploits, it is likely used by a wide range of actors, including script kiddies and financially motivated groups. CISA KEV: Not Listed
Network Intrusion Detection Systems (NIDS) can be configured to detect malicious HTTP requests with excessively long Authenticate headers, especially those containing non-ASCII characters.
Web Application Firewalls (WAFs) can be deployed to filter out malicious HTTP requests based on header length and content.
Log analysis of Domino server logs (including DOMLOG.NSF) for unusual activity, such as frequent server crashes or errors related to authentication.
Monitor for unexpected process terminations or restarts of the Domino web server.
Examine memory dumps (if available after a crash) for evidence of buffer overflows and overwritten data structures.
Patch immediately: Upgrade to a patched version of Lotus Domino (R5.0.10 or later). This is the primary and most effective remediation step.
Implement a Web Application Firewall (WAF) to filter malicious HTTP requests. Configure the WAF to block requests with excessively long Authenticate headers or those containing suspicious characters.
Enforce strong input validation at the application level. Ensure that all user-supplied data, including HTTP headers, is properly validated and sanitized before being processed.
Regularly scan the network for vulnerable systems using vulnerability scanners.
Implement a robust logging and monitoring solution to detect and alert on suspicious activity.
Segment the network to limit the impact of a successful exploit.