CVE-2019-7629 in TinTin++
Summary
by MITRE
Stack-based buffer overflow in the strip_vt102_codes function in TinTin++ 2.01.6 and WinTin++ 2.01.6 allows remote attackers to execute arbitrary code by sending a long message to the client.
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Analysis
by VulDB Data Team • 07/11/2023
The vulnerability identified as CVE-2019-7629 represents a critical stack-based buffer overflow flaw within the TinTin++ and WinTin++ text-based multi-user dungeon clients. This issue affects versions 2.01.6 of both client implementations and stems from insufficient input validation in the strip_vt102_codes function. The vulnerability manifests when these clients process incoming messages containing excessive data sequences that exceed the allocated stack buffer space, creating an exploitable condition that can be remotely triggered by malicious actors.
The technical exploitation of this vulnerability occurs through a classic stack buffer overflow attack vector where an attacker crafts a specially formatted message containing an excessive number of VT102 control codes that exceed the predetermined buffer limits within the strip_vt102_codes function. This function is responsible for processing and removing VT102 terminal control sequences from incoming text, but fails to properly validate the length of input data before copying it into a fixed-size stack buffer. The flaw directly corresponds to CWE-121 Stack-based Buffer Overflow, which is classified as a critical weakness in software security. When the buffer overflow occurs, it can overwrite adjacent memory locations including return addresses and function pointers, potentially allowing attackers to redirect execution flow and execute arbitrary code with the privileges of the affected client process.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with a means to gain unauthorized control over client systems running TinTin++ or WinTin++. Since these clients are commonly used in MUD (Multi-User Dungeon) environments and other text-based network applications, attackers can leverage this vulnerability to compromise user sessions, steal sensitive information, or establish persistent access points within network environments. The remote nature of the attack means that exploitation does not require local system access, making it particularly dangerous for users who connect to potentially hostile MUD servers or network services. This vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation, as successful exploitation could lead to privilege escalation and further system compromise.
Mitigation strategies for this vulnerability should focus on immediate patching of affected software versions, implementing input validation controls, and network-level protections. Users should upgrade to patched versions of TinTin++ and WinTin++ where available, as vendors typically address such buffer overflow issues through proper bounds checking and memory management. Additional defensive measures include implementing network segmentation to limit exposure to potentially malicious MUD servers, deploying intrusion detection systems that can identify suspicious VT102 control code sequences, and configuring client applications to reject overly long input sequences. Security monitoring should focus on detecting anomalous traffic patterns and unusual client behavior that might indicate exploitation attempts. Organizations should also consider implementing application whitelisting policies to restrict execution of untrusted client software and maintain regular vulnerability assessments to identify similar buffer overflow conditions in other legacy applications. The vulnerability demonstrates the importance of proper input validation and memory management practices, particularly in applications that process untrusted network data streams.