CVE-2002-0913 in Slurp
Summary
by MITRE
Format string vulnerability in log_doit function of Slurp NNTP client 1.1.0 allows a malicious news server to execute arbitrary code on the client via format strings in a server response.
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Analysis
by VulDB Data Team • 10/26/2024
The vulnerability identified as CVE-2002-0913 represents a critical format string flaw within the Slurp NNTP client version 1.1.0 that exposes users to remote code execution risks. This issue resides in the log_doit function which processes server responses during NNTP (Network News Transfer Protocol) operations. The vulnerability arises when the client receives malformed responses from malicious news servers that contain format specifiers such as %s, %d, or %x within the server-generated content. When the log_doit function processes these untrusted inputs without proper validation or sanitization, it inadvertently interprets the format specifiers as instructions for variable expansion, leading to potential information disclosure, stack corruption, or arbitrary code execution on the victim's system.
This vulnerability operates under the broader category of CWE-134, which specifically addresses the use of format strings in a manner that allows attackers to control the format string parameters. The attack vector involves a malicious NNTP server that crafts specially formatted responses designed to exploit the vulnerable log_doit function. When the Slurp client processes these responses, the format string vulnerability enables an attacker to manipulate the program's execution flow by writing arbitrary values to memory locations or by causing the program to read from or write to unintended memory addresses. The operational impact extends beyond simple information disclosure, as successful exploitation could allow remote attackers to execute arbitrary commands with the privileges of the user running the Slurp client, effectively compromising the entire system.
The security implications of this vulnerability align with ATT&CK technique T1059.007, which covers the use of command and scripting interpreter for execution, as the exploitation could lead to arbitrary code execution on the compromised system. The vulnerability also maps to T1555.003, which deals with credentials from password storage components, since successful exploitation could potentially expose sensitive information stored in memory. The attack scenario typically involves a user connecting to a malicious NNTP server that responds with carefully crafted format string payloads. The Slurp client, upon processing these responses, becomes vulnerable to stack-based buffer overflows or information leaks that can be leveraged to achieve remote code execution. The vulnerability affects systems where the Slurp client is used for news server communication, particularly in environments where users may connect to untrusted NNTP servers without proper security controls.
Mitigation strategies for this vulnerability require immediate patching of the Slurp NNTP client to version 1.1.1 or later, which contains the necessary fixes for the format string handling in the log_doit function. Additionally, administrators should implement network segmentation to limit access to NNTP servers and consider deploying network monitoring tools to detect suspicious NNTP traffic patterns. The recommended approach includes validating all server responses before processing them through the log_doit function, implementing proper input sanitization, and ensuring that format strings are always properly escaped or parameterized. Organizations should also consider using alternative NNTP clients that have been verified to handle format strings securely, and establish security policies that restrict user access to potentially malicious NNTP servers. System hardening measures such as stack protection mechanisms, address space layout randomization, and non-executable stack protections can provide additional defense-in-depth measures against exploitation attempts. The vulnerability serves as a reminder of the critical importance of proper input validation and secure coding practices in network applications, particularly those handling untrusted data from remote sources.