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 is vulnerable to multiple integer overflows in its HTTP server, allowing remote attackers to trigger a denial-of-service (DoS) condition or potentially achieve remote code execution (RCE). Malicious actors can exploit this vulnerability by sending specially crafted HTTP headers with manipulated length variables, leading to memory corruption and program instability. This poses a significant risk to systems running the affected framework.
Step 1: Crafted Request: The attacker crafts a malicious HTTP request targeting the vulnerable Novell XTier framework. This request includes HTTP headers with specially crafted length variables that are designed to cause an integer overflow.
Step 2: Header Parsing: The vulnerable HTTP server receives the malicious request and begins parsing the HTTP headers.
Step 3: Integer Overflow: The server attempts to process the manipulated length variables. Due to the lack of proper input validation, the large values cause an integer overflow during calculations related to memory allocation or buffer sizing.
Step 4: Memory Corruption: The overflowed values are used in subsequent memory operations. This leads to the allocation of insufficient memory or incorrect buffer sizes.
Step 5: Buffer Overflow/DoS: When the server attempts to copy the header data into the undersized buffer, a buffer overflow occurs. This overwrites adjacent memory regions, potentially corrupting critical program data, leading to a server crash (DoS). In some cases, this could be exploited to overwrite function pointers or other control data, leading to remote code execution (RCE).
The vulnerability stems from integer overflows within the HTTP server's header parsing logic in Novell XTier framework 3.1.8. Specifically, the code fails to properly validate the size of header length variables before using them in memory allocation or other calculations. By providing extremely large values for these length variables, an attacker can cause an integer overflow. This leads to a smaller-than-expected value being used for subsequent memory operations. This can cause a buffer overflow when the server attempts to copy the header data into a buffer that is too small, leading to memory corruption. The corrupted memory can then be leveraged to cause a denial-of-service (DoS) by crashing the server, or, in more sophisticated attacks, to overwrite critical program data and potentially achieve remote code execution (RCE). The root cause is a lack of input validation and the use of integer arithmetic without proper bounds checking.