CVE-2017-7467 in Minicom
Summary
by MITRE
A buffer overflow flaw was found in the way minicom before version 2.7.1 handled VT100 escape sequences. A malicious terminal device could potentially use this flaw to crash minicom, or execute arbitrary code in the context of the minicom process.
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Analysis
by VulDB Data Team • 04/06/2023
The vulnerability identified as CVE-2017-7467 represents a critical buffer overflow flaw within the minicom terminal emulator software, specifically affecting versions prior to 2.7.1. This issue arises from inadequate input validation when processing VT100 escape sequences, which are standard control character sequences used for terminal formatting and cursor control in Unix-like systems. The flaw exists in the software's handling of terminal communication protocols, where malicious input can manipulate the program's memory management during escape sequence processing. Minicom, being a serial communication program that provides terminal emulation capabilities, processes these escape sequences to control display behavior and terminal functions, making it a prime target for exploitation through malformed input.
The technical implementation of this vulnerability stems from improper bounds checking in the buffer management routines that handle VT100 escape sequences. When minicom receives input containing specially crafted escape sequences, the program fails to validate the length of data being processed against allocated buffer sizes. This allows an attacker to overflow the intended buffer space, potentially overwriting adjacent memory locations including return addresses and program variables. The vulnerability manifests as a classic stack-based buffer overflow when the program attempts to copy user-supplied escape sequence data into a fixed-size buffer without proper length verification. This flaw directly maps to CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite stack data.
The operational impact of CVE-2017-7467 extends beyond simple denial of service to potential remote code execution capabilities, making it particularly dangerous in networked environments. An attacker controlling a malicious terminal device or network connection can exploit this vulnerability to crash the minicom process or potentially execute arbitrary code with the privileges of the minicom user. This represents a significant threat to system security since minicom often runs with elevated privileges during serial communication sessions, particularly when used for system administration tasks or embedded system debugging. The attack vector is particularly concerning because it leverages legitimate terminal communication protocols, making detection more difficult and allowing exploitation through normal operational procedures. From an ATT&CK framework perspective, this vulnerability aligns with techniques involving command and control communication, privilege escalation, and execution through legitimate system processes.
Mitigation strategies for this vulnerability should focus on immediate software updates to version 2.7.1 or later, which contain proper bounds checking and input validation for VT100 escape sequences. System administrators should also implement network segmentation and access controls to limit exposure of minicom instances to untrusted terminal devices. Additional defensive measures include monitoring for unusual terminal communication patterns and implementing input sanitization at network boundaries. The vulnerability highlights the importance of secure coding practices in terminal emulators and communication software, particularly regarding buffer management and input validation. Organizations should conduct comprehensive vulnerability assessments to identify other instances of similar flaws in legacy terminal software and communication tools. Regular security updates and proper patch management procedures are essential to prevent exploitation of such buffer overflow vulnerabilities in critical system components.