CVE-1999-1483 in Svgalib
Summary
by MITRE
buffer overflow in zgv in svgalib 1.2.10 and earlier allows local users to execute arbitrary code via a long home environment variable.
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Analysis
by VulDB Data Team • 11/11/2024
The vulnerability identified as CVE-1999-1483 represents a critical buffer overflow flaw within the zgv image viewer application that utilizes the svgalib graphics library. This issue affects versions 1.2.10 and earlier of the svgalib library, creating a significant security risk for systems that rely on this graphics framework for display operations. The vulnerability specifically manifests when the application processes the HOME environment variable, which is a fundamental system parameter used by Unix-like operating systems to determine user home directories and application configuration locations.
The technical implementation of this buffer overflow occurs due to inadequate input validation within the zgv application's handling of environment variables. When a local user sets an excessively long HOME environment variable, the application fails to properly bounds-check the input data before copying it into a fixed-size buffer. This programming oversight creates a condition where user-supplied data can overwrite adjacent memory locations, potentially corrupting program execution flow and allowing for arbitrary code execution. The vulnerability is classified as a classic stack-based buffer overflow, where the overflow occurs in the stack memory region allocated for local variables and function call information. This type of vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows adjacent memory to be overwritten.
The operational impact of CVE-1999-1483 is particularly concerning for local privilege escalation scenarios, as it requires only local user access to exploit the vulnerability. An attacker with basic system access can manipulate the HOME environment variable to trigger the buffer overflow and execute malicious code with the privileges of the affected process. This vulnerability can be exploited to gain unauthorized access to system resources, potentially leading to complete system compromise. The attack vector is relatively simple to execute since it only requires setting an environment variable, making it accessible to attackers with minimal technical expertise. The vulnerability demonstrates a fundamental flaw in input validation practices that was prevalent in software development during the late 1990s, highlighting the importance of proper memory management and bounds checking in application security.
Mitigation strategies for this vulnerability involve multiple approaches that address both immediate remediation and long-term security improvements. The most direct solution is to upgrade to svgalib versions 1.2.11 or later, where the buffer overflow has been patched through proper bounds checking implementation. System administrators should also implement environment variable sanitization practices, particularly in multi-user systems where local users might attempt exploitation. Additionally, the principle of least privilege should be enforced by limiting the execution permissions of the zgv application and ensuring that it runs with minimal required privileges. This vulnerability also underscores the importance of following secure coding practices such as those outlined in the CERT Secure Coding Standards, which emphasize the necessity of input validation and bounds checking to prevent buffer overflow conditions. Organizations should consider implementing runtime protections such as stack canaries and address space layout randomization to make exploitation more difficult even if similar vulnerabilities exist in other applications. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting the use of local applications with insufficient input validation to gain elevated system access.