CVE-2002-0501 in DNS Server
Summary
by MITRE
Format string vulnerability in log_print() function of Posadis DNS server before version m5pre2 allows local users and possibly remote attackers to execute arbitrary code via format strings that are inserted into logging messages.
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Analysis
by VulDB Data Team • 04/12/2019
The CVE-2002-0501 vulnerability represents a critical format string flaw within the Posadis DNS server software, specifically within the log_print() function that precedes version m5pre2. This type of vulnerability falls under the broader category of CWE-134 which defines weaknesses related to format string vulnerabilities in programming languages like C and C++ where improper handling of format specifiers can lead to severe security implications. The vulnerability manifests when the application processes user-supplied input directly within format string operations without proper sanitization or validation, creating an opportunity for malicious actors to manipulate the execution flow of the application.
The technical exploitation of this vulnerability occurs when the log_print() function receives input data that contains format specifiers such as %s, %d, or %x without appropriate handling mechanisms. When the application processes these format specifiers, it can lead to information disclosure, application crashes, or more critically, arbitrary code execution. Local users can exploit this by crafting malicious input that, when logged, triggers the format string vulnerability. Remote attackers may also leverage this weakness if the DNS server accepts user input that gets logged, though the exact scope of remote exploitation depends on the specific implementation details and network configuration of the affected system.
The operational impact of this vulnerability extends beyond simple code execution, as it can provide attackers with complete control over the affected DNS server. This control enables malicious actors to manipulate DNS records, redirect traffic to malicious sites, or even use the compromised server as a pivot point for further attacks within the network. The vulnerability affects the integrity and availability of the DNS infrastructure, potentially leading to widespread service disruption or data compromise. From an attacker's perspective, this vulnerability aligns with techniques described in the MITRE ATT&CK framework under the T1059.007 technique for command and scripting interpreter, where adversaries can execute arbitrary commands through vulnerable applications. The vulnerability also represents a significant risk to the confidentiality of information, as attackers can potentially extract sensitive data from memory locations through format string exploitation.
Mitigation strategies for this vulnerability require immediate patching of the Posadis DNS server to version m5pre2 or later, which contains the necessary fixes for the format string handling. Organizations should also implement input validation measures to prevent user-supplied data from being directly processed within logging functions. The principle of least privilege should be enforced by running the DNS server with minimal required permissions, limiting the potential impact of successful exploitation. Additionally, system administrators should monitor logs for suspicious patterns that might indicate exploitation attempts and implement intrusion detection systems to identify potential attacks targeting this vulnerability. Security auditing of similar applications should be conducted to identify other instances of improper format string handling, as this class of vulnerability often appears in legacy code bases where proper input validation practices were not consistently applied.