CVE-2003-0452 in osh
Summary
by MITRE
Buffer overflows in osh before 1.7-11 allow local users to execute arbitrary code and bypass shell restrictions via (1) long environment variables or (2) long "file redirections."
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Analysis
by VulDB Data Team • 04/30/2019
The vulnerability identified as CVE-2003-0452 represents a critical buffer overflow issue affecting the osh shell version 1.7-10 and earlier. This flaw resides in the shell's handling of environment variables and file redirection operations, creating exploitable conditions that can be leveraged by local attackers to execute arbitrary code and circumvent existing shell security measures. The vulnerability demonstrates the classic characteristics of buffer overflow exploits that have long been recognized as fundamental security weaknesses in software systems, particularly those involving unbounded input handling and memory management.
The technical implementation of this vulnerability stems from insufficient bounds checking within the osh shell's processing of environment variables and file redirection operations. When a local user provides excessively long input strings through either environment variables or file redirection constructs, the shell fails to properly validate the input length before attempting to store or process these values in fixed-size memory buffers. This deficiency creates predictable buffer overflow conditions that can be systematically exploited to overwrite adjacent memory locations, potentially including return addresses, function pointers, or other critical control data. The vulnerability specifically affects the shell's internal parsing and execution mechanisms, where environment variables are processed during shell initialization and file redirection operations are handled during command execution.
The operational impact of CVE-2003-0452 extends beyond simple privilege escalation to encompass complete system compromise through arbitrary code execution. Local attackers can leverage this vulnerability to execute malicious code with the privileges of the affected shell process, potentially leading to privilege escalation, data theft, or system takeover. The ability to bypass shell restrictions represents a particularly dangerous aspect of this vulnerability, as it undermines the fundamental security model that relies on shell access controls and command filtering mechanisms. Attackers can craft specific environment variables or redirection sequences that not only trigger the buffer overflow but also position the execution flow to jump to malicious code locations, effectively circumventing traditional shell security measures. This vulnerability aligns with attack patterns documented in the ATT&CK framework under privilege escalation and defense evasion techniques, specifically targeting the execution and persistence phases of adversarial operations.
Mitigation strategies for this vulnerability center on immediate software updates and system hardening measures. The most effective remediation involves upgrading to osh version 1.7-11 or later, which includes proper input validation and buffer size checking mechanisms. System administrators should implement comprehensive patch management processes to ensure all affected systems receive timely updates. Additional protective measures include implementing environment variable length restrictions, employing input sanitization routines, and deploying runtime monitoring solutions that can detect anomalous buffer usage patterns. The vulnerability demonstrates the importance of following secure coding practices as outlined in CWE guidelines, particularly CWE-121 for stack-based buffer overflows and CWE-122 for heap-based buffer overflows. Organizations should also consider implementing principle of least privilege models and regular security audits to identify and remediate similar vulnerabilities across their software infrastructure, as buffer overflows remain among the most frequently exploited classes of vulnerabilities in cybersecurity incidents.