CVE-2012-6122 in CHICKEN
Summary
by MITRE
Buffer overflow in the thread scheduler in Chicken before 4.8.0.1 allows attackers to cause a denial of service (crash) by opening a file descriptor with a large integer value.
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Analysis
by VulDB Data Team • 11/01/2019
The vulnerability identified as CVE-2012-6122 represents a critical buffer overflow condition within the thread scheduler component of the Chicken Scheme implementation prior to version 4.8.0.1. This flaw exists in the manner in which the system handles file descriptor integers during thread scheduling operations, creating a potential pathway for malicious exploitation that can result in system instability and service disruption. The vulnerability specifically targets the internal buffer management mechanisms that govern how file descriptor values are processed within the threading subsystem.
The technical root cause of this vulnerability stems from inadequate input validation and buffer size management within the thread scheduler's file descriptor handling code. When an attacker opens a file descriptor with an excessively large integer value, the system fails to properly validate the magnitude of the file descriptor number against the allocated buffer boundaries. This allows the integer value to overflow into adjacent memory regions, corrupting critical thread scheduler data structures and potentially leading to arbitrary code execution or system crash. The flaw manifests as a classic buffer overflow condition where the integer value exceeds the expected range for file descriptor handling, triggering memory corruption in the scheduler's internal data structures.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it can be exploited to cause system instability and potentially enable more sophisticated attacks. An attacker capable of opening file descriptors with large integer values can trigger the buffer overflow condition, resulting in thread scheduler crashes that may affect the entire application or system stability. This vulnerability particularly impacts systems running Chicken Scheme implementations where multiple threads are actively managed, as the thread scheduler's memory corruption can propagate through the threading subsystem. The vulnerability's exploitation requires minimal privileges and can be executed through standard file descriptor operations, making it particularly dangerous in multi-user or shared hosting environments.
Mitigation strategies for CVE-2012-6122 primarily focus on updating to Chicken Scheme version 4.8.0.1 or later, which includes patched buffer management routines and enhanced input validation for file descriptor handling. System administrators should implement strict file descriptor limits and monitoring mechanisms to detect anomalous file descriptor usage patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a specific instance of improper input validation that violates secure coding practices. From an ATT&CK framework perspective, this vulnerability maps to technique T1499.004, which covers network denial of service attacks, and could potentially enable further exploitation through privilege escalation or system compromise if not properly addressed. Organizations should also consider implementing runtime protections such as address space layout randomization and stack canaries to reduce the effectiveness of potential exploitation attempts.