CVE-2002-1788 in Kim Storm
Summary
by MITRE
Format string vulnerability in the nn_exitmsg function in nn 6.6.0 through 6.6.3 allows remote NNTP servers to execute arbitrary code via format strings in server responses.
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Analysis
by VulDB Data Team • 06/10/2018
The vulnerability identified as CVE-2002-1788 represents a critical format string flaw within the Network News Transfer Protocol implementation, specifically affecting the nn news server software versions 6.6.0 through 6.6.3. This vulnerability resides in the nn_exitmsg function which processes server responses and handles user input without proper validation or sanitization. The flaw allows remote attackers to manipulate format specifiers within server responses, potentially leading to arbitrary code execution on the affected system. The vulnerability is particularly dangerous as it operates at the protocol level where legitimate network traffic is processed, making it difficult to distinguish between normal and malicious input.
The technical nature of this vulnerability aligns with CWE-134, which specifically addresses the use of format strings in functions like printf without proper validation, creating opportunities for attackers to inject malicious format specifiers. When the nn_exitmsg function processes server responses containing format strings, the application fails to properly escape or validate these inputs before passing them to formatting functions. This creates a classic buffer overflow scenario where attackers can manipulate memory layout, potentially overwriting critical function pointers or return addresses to redirect execution flow. The vulnerability operates under the ATT&CK framework category of T1059.007 for command and scripting interpreter, as successful exploitation would enable arbitrary code execution through the compromised server process.
The operational impact of this vulnerability extends beyond simple remote code execution, as it fundamentally compromises the integrity of the news server infrastructure. An attacker could leverage this flaw to gain unauthorized access to the system, potentially escalating privileges or establishing persistent backdoors within the network. The vulnerability affects systems that rely on nn news servers for handling newsgroup communications, making it particularly dangerous for organizations maintaining news server infrastructure. The remote nature of the attack means that exploitation can occur from anywhere on the internet without requiring local access or authentication, significantly increasing the attack surface.
Mitigation strategies for CVE-2002-1788 should focus on immediate patching of affected systems, with version 6.6.4 and later releases containing the necessary fixes for this vulnerability. Organizations should implement network segmentation to limit exposure of news server infrastructure and consider disabling unnecessary NNTP services when not actively required. Input validation should be enhanced to filter or escape format specifiers within server responses, and the application should be configured to use secure coding practices that prevent direct formatting of user-supplied data. Additionally, monitoring should be implemented to detect unusual patterns in server responses that might indicate exploitation attempts, and network intrusion detection systems should be configured to alert on suspicious NNTP traffic patterns. The vulnerability demonstrates the importance of proper input validation in network protocols and highlights the need for secure coding practices that prevent format string vulnerabilities in server applications.