Source: cve@mitre.org
Multiple integer overflows in the HTTP server in the Novell XTier framework 3.1.8 allow remote attackers to cause a denial of service (service crash) or possibly execute arbitrary code via crafted header length variables.
Novell XTier framework 3.1.8 suffers from multiple integer overflow vulnerabilities in its HTTP server, allowing remote attackers to trigger a denial of service (DoS) or potentially remote code execution (RCE). Malicious actors can exploit these flaws by sending specially crafted HTTP headers with manipulated length variables, leading to memory corruption and system instability. Successful exploitation could result in complete system compromise or service disruption.
Step 1: Payload Delivery: The attacker crafts a malicious HTTP request. This request contains HTTP headers with manipulated length variables, designed to cause an integer overflow when processed by the Novell XTier HTTP server.
Step 2: Header Parsing: The XTier HTTP server receives the crafted request and begins parsing the HTTP headers.
Step 3: Integer Overflow: During header processing, the server attempts to calculate memory allocation sizes or perform other arithmetic operations using the attacker-controlled header length variables. Due to the lack of proper input validation, the excessively large values cause an integer overflow.
Step 4: Memory Corruption: The integer overflow leads to incorrect memory allocation or other memory corruption issues, such as a buffer overflow.
Step 5: Denial of Service (DoS) or RCE: The memory corruption can cause the server to crash, resulting in a denial of service. In some cases, if the attacker can control the data written to the corrupted memory regions, they may be able to achieve remote code execution.
The vulnerability stems from multiple integer overflows within the HTTP server's handling of header length variables. Specifically, the framework fails to properly validate the size of incoming HTTP headers before allocating memory or performing arithmetic operations. By providing excessively large values for header length fields, an attacker can trigger an integer overflow. This overflow can then lead to incorrect memory allocation, potentially resulting in a buffer overflow or other memory corruption issues. The root cause is a lack of input validation and bounds checking on the header length parameters, allowing attackers to manipulate these values beyond the intended limits. This can lead to a crash (DoS) or, in more severe cases, allow for the execution of arbitrary code if the attacker can control the data written to the corrupted memory regions.
Due to the age of the vulnerability, it's less likely to be directly targeted by sophisticated APTs. However, it could be incorporated into broader attack campaigns targeting vulnerable legacy systems. It is unlikely to be listed on the CISA KEV at this time, given its age and the availability of patches.
Network Intrusion Detection Systems (NIDS) can be configured to detect malicious HTTP requests with unusually large header lengths or specific header values known to trigger the vulnerability.
Web Application Firewalls (WAFs) can be deployed to filter and block malicious HTTP requests based on header size and content.
Log analysis of HTTP server logs to identify requests with suspicious header lengths or patterns.
Host-based Intrusion Detection Systems (HIDS) can monitor for unexpected process crashes or memory corruption events related to the XTier HTTP server.
Upgrade to a patched version of the Novell XTier framework that addresses the integer overflow vulnerabilities. If upgrading is not possible, apply any available vendor-provided patches.
Implement a Web Application Firewall (WAF) to filter and block malicious HTTP requests.
Enforce strict input validation on all HTTP header fields to prevent integer overflows.
Regularly scan the system for vulnerabilities and apply security updates promptly.
Implement a defense-in-depth strategy, including network segmentation, intrusion detection/prevention systems, and host-based security measures.
Monitor HTTP server logs for suspicious activity and anomalous header patterns.