CVE-2000-0388 in FreeBSD
Summary
by MITRE
buffer overflow in freebsd libmytinfo library allows local users to execute commands via a long termcap environmental variable.
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Analysis
by VulDB Data Team • 04/03/2025
The vulnerability identified as CVE-2000-0388 represents a critical buffer overflow flaw within the FreeBSD libmytinfo library that enables local attackers to execute arbitrary commands through manipulation of the TERM environment variable. This vulnerability resides in the terminal capability handling mechanisms that are fundamental to Unix-like operating systems, where applications rely on terminal descriptions to properly render content and handle user interactions. The libmytinfo library serves as a critical component in terminal information management, storing and retrieving terminal capabilities through the termcap database format that has been a standard component in Unix systems for decades.
The technical implementation of this vulnerability stems from insufficient bounds checking within the library's parsing routines for terminal capability descriptions. When applications process the TERM environment variable, they typically invoke functions within libmytinfo to retrieve terminal capabilities from the termcap database. The buffer overflow occurs during the parsing of terminal descriptions where the library fails to validate the length of input data from the TERM variable, allowing an attacker to overflow a fixed-size buffer and overwrite adjacent memory locations. This memory corruption can be carefully crafted to overwrite return addresses or function pointers, enabling the execution of arbitrary code with the privileges of the affected process.
The operational impact of this vulnerability extends beyond simple local privilege escalation as it represents a classic buffer overflow attack vector that can be exploited by any local user with access to modify environment variables. The attack requires no network connectivity and can be executed entirely within the local system context, making it particularly dangerous for multi-user environments where users may have varying privilege levels. The vulnerability affects systems running FreeBSD versions that include the vulnerable libmytinfo library, potentially compromising the integrity of the entire system if exploited successfully. The exploitation can lead to unauthorized privilege escalation, data compromise, or even complete system takeover depending on the target process and its privilege level.
Mitigation strategies for CVE-2000-0388 should prioritize immediate patching of affected FreeBSD systems with updated versions of the libmytinfo library that include proper bounds checking mechanisms. System administrators should implement strict environment variable validation and consider disabling unnecessary terminal capability processing in applications that do not require full terminal description support. The vulnerability aligns with CWE-121, which categorizes buffer overflow conditions as a fundamental weakness in software design, and demonstrates characteristics consistent with ATT&CK technique T1068, which involves local privilege escalation through exploitation of system vulnerabilities. Organizations should also implement monitoring for unusual environment variable modifications and consider restricting user access to terminal capability files to minimize potential attack surfaces. Regular security audits and vulnerability assessments should include checks for outdated terminal capability libraries to prevent similar issues from remaining undetected in the system infrastructure.