CVE-2005-4817 in TMSNC
Summary
by MITRE
Format string vulnerability in ui.c in Textbased MSN Client (TMSNC) before 0.2.5 allows attackers to cause a denial of service and possibly execute arbitrary code via unknown attack vectors that cause format strings to be injected into the wprintw function.
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Analysis
by VulDB Data Team • 07/16/2018
The CVE-2005-4817 vulnerability represents a critical format string flaw within the Textbased MSN Client (TMSNC) software ecosystem, specifically within the ui.c component. This vulnerability existed in versions prior to 025 and fundamentally compromised the application's ability to handle user input securely. The flaw manifests when attacker-controlled data is processed through the wprintw function, which is a curses library function used for formatted output rendering. The vulnerability classification aligns with CWE-134 which specifically addresses the use of format strings inappropriately, making it a direct descendant of the well-known format string attack patterns that have plagued software systems for decades.
The technical exploitation of this vulnerability occurs when malicious input data contains format specifiers that are subsequently passed to the wprintw function without proper sanitization or validation. This creates an environment where an attacker can manipulate the program's execution flow by injecting format string directives into the output rendering pipeline. The impact extends beyond simple denial of service scenarios, as the vulnerability could potentially enable arbitrary code execution through carefully crafted input sequences that exploit the underlying format string handling mechanisms. This represents a classic example of how improper input validation can lead to severe security implications in networked client applications.
The operational impact of this vulnerability within the TMSNC context is particularly concerning given that it affects a text-based instant messaging client that would typically process data from remote peers. Attackers could leverage this flaw to either crash the application through malformed input causing segmentation faults or potentially execute malicious code with the privileges of the running process. The vulnerability's potential for remote code execution makes it especially dangerous in environments where the client software operates in a multi-user or networked context. This type of vulnerability directly maps to ATT&CK technique T1059.007 for command and scripting interpreter, as it enables attackers to execute arbitrary commands through the compromised application's output rendering mechanisms.
Mitigation strategies for CVE-2005-4817 should focus on immediate version updates to TMSNC 0.2.5 or later, which contain the necessary patches to address the format string vulnerability. Additionally, implementing proper input sanitization measures within the application's input handling pipeline would provide defense-in-depth protection against similar vulnerabilities. The fix typically involves ensuring that user-supplied data is properly escaped or validated before being passed to formatting functions, particularly those that handle format specifiers. Organizations should also consider implementing network-level monitoring to detect potential exploitation attempts and establish proper input validation procedures for all user-facing interfaces. The vulnerability demonstrates the critical importance of proper input handling and the potential for format string vulnerabilities to serve as initial access vectors in broader attack campaigns.