CVE-2018-7582 in WebLog Expert Web Server Enterprise
Summary
by MITRE
WebLog Expert Web Server Enterprise 9.4 allows Remote Denial Of Service (daemon crash) via a long HTTP Accept Header to TCP port 9991.
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Analysis
by VulDB Data Team • 09/25/2025
The vulnerability identified as CVE-2018-7582 affects WebLog Expert Web Server Enterprise version 9.4, presenting a remote denial of service condition that can cause the daemon to crash. This issue manifests when an attacker sends a malformed HTTP Accept header to the server's TCP port 9991, which serves as the default listening port for this web server implementation. The flaw represents a classic buffer overflow condition where the server fails to properly validate input length before processing the Accept header field, leading to memory corruption and subsequent service termination.
The technical nature of this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow scenarios. The attack vector operates through the HTTP protocol layer where the server processes incoming requests without adequate bounds checking on header values. When the Accept header exceeds predetermined memory allocation limits, the web server daemon encounters a memory access violation that results in an abrupt crash and service unavailability. This type of vulnerability falls under the ATT&CK technique T1499.004, specifically targeting network denial of service conditions through service interruption.
The operational impact of CVE-2018-7582 extends beyond simple service disruption, as it can affect business continuity and availability of web applications relying on this server implementation. Organizations utilizing WebLog Expert Web Server Enterprise 9.4 may experience unauthorized service interruption, potentially leading to data access limitations and operational downtime. The vulnerability affects systems where the web server is exposed to external networks, making it particularly dangerous in production environments where continuous availability is critical. The daemon crash represents a complete service outage that requires manual intervention to restore normal operations, including server restarts and potential log analysis to identify attack patterns.
Mitigation strategies for this vulnerability should include immediate patching of the WebLog Expert Web Server Enterprise to version 9.5 or later, which contains the necessary fixes for input validation. Network administrators should implement proper access controls and firewall rules to restrict access to TCP port 9991, limiting exposure to only trusted sources. Additionally, implementing intrusion detection systems with signature-based detection for long HTTP headers can help identify and block malicious traffic patterns. The recommended approach aligns with the NIST Cybersecurity Framework's protective measures, particularly focusing on vulnerability management and information protection. Organizations should also consider deploying web application firewalls to filter out malformed HTTP requests before they reach the vulnerable server component, providing an additional layer of defense against similar buffer overflow attacks.