CVE-2007-3659 in FreeWRL
Summary
by MITRE
Buffer overflow in the doBrowserAction function in FreeWRL 1.19.3 allows local users to execute arbitrary code via a crafted BROWSER environment variable. NOTE: it is not clear whether this issue crosses privilege boundaries.
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Analysis
by VulDB Data Team • 09/05/2018
The vulnerability described in CVE-2007-3659 represents a critical buffer overflow flaw within the FreeWRL 1.19.3 web browser implementation that poses significant security risks to systems utilizing this software. FreeWRL is an open-source web browser designed to render vrml files and other 3d graphics content, and this particular vulnerability exists within the doBrowserAction function which processes browser actions. The flaw specifically manifests when the application processes a crafted BROWSER environment variable, creating an opportunity for malicious code execution. This type of vulnerability falls under the category of buffer overflow attacks as defined by CWE-121, which occurs when a program writes data beyond the boundaries of a fixed-length buffer, potentially corrupting adjacent memory locations and allowing attackers to overwrite critical program data or execution control structures.
The technical implementation of this vulnerability stems from inadequate input validation within the doBrowserAction function where the BROWSER environment variable is processed without proper bounds checking. When a local user crafts a specially designed environment variable that exceeds the allocated buffer size, the excess data overflows into adjacent memory regions, potentially overwriting return addresses, function pointers, or other critical execution context information. This overflow condition creates an exploitable state where the attacker can manipulate the program's execution flow to redirect control to malicious code. The vulnerability's impact is particularly concerning because it operates within the local user context, meaning that an attacker who already has access to the system can leverage this flaw to escalate privileges or execute arbitrary commands with the privileges of the running FreeWRL process.
From an operational perspective, this vulnerability presents a substantial risk to systems where FreeWRL is installed and actively used, particularly in environments where local users might have access to system resources or where the browser is used to process untrusted content. The uncertainty regarding whether this issue crosses privilege boundaries indicates that the vulnerability might be exploitable in scenarios where local users can influence environment variables that FreeWRL processes, potentially allowing for privilege escalation if the application runs with elevated privileges. The attack vector requires local access to the system and knowledge of how to craft the malicious BROWSER environment variable, making it less likely to be exploited remotely but still posing a significant threat in compromised environments. This vulnerability aligns with ATT&CK technique T1068 which describes privilege escalation through local exploitation, and specifically addresses the use of environment variables as attack vectors.
The mitigation strategies for this vulnerability should focus on implementing proper bounds checking and input validation within the doBrowserAction function to prevent buffer overflows from occurring. System administrators should ensure that FreeWRL is updated to the latest available version where this vulnerability has been patched, as the original version 1.19.3 contained the exploitable buffer overflow condition. Additionally, environment variable handling should be reviewed to ensure that applications properly sanitize input data before processing, particularly when dealing with environment variables that can be manipulated by local users. Security measures including stack canaries, address space layout randomization, and non-executable stack protections can provide additional layers of defense against exploitation attempts. Organizations should also consider implementing least privilege principles for running FreeWRL applications and monitoring for unusual environment variable modifications that might indicate exploitation attempts, as this vulnerability represents a classic example of how environment variable manipulation can lead to arbitrary code execution in vulnerable applications.