CVE-2006-7252 in FreeBSD
Summary
by MITRE
Integer overflow in the calloc function in libc/stdlib/malloc.c in jemalloc in libc for FreeBSD 6.4 and NetBSD makes it easier for context-dependent attackers to perform memory-related attacks such as buffer overflows via a large size value, which triggers a memory allocation of one byte.
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Analysis
by VulDB Data Team • 02/18/2019
The vulnerability described in CVE-2006-7252 represents a critical integer overflow flaw within the memory allocation subsystem of FreeBSD 6.4 and NetBSD operating systems. This issue specifically affects the calloc function implementation within jemalloc, which serves as a memory allocator component in these systems. The flaw manifests when an attacker provides a large size value to the calloc function, causing the underlying malloc implementation to miscalculate the required memory allocation size. This miscalculation occurs due to integer overflow conditions that result in the system allocating significantly less memory than requested, typically only one byte instead of the intended large memory block. The vulnerability is classified under CWE-190 as an integer overflow error, which directly enables attackers to manipulate memory allocation behavior in ways that can compromise system stability and security.
The operational impact of this vulnerability extends beyond simple memory allocation errors, creating conditions that facilitate more sophisticated memory-related attacks. When the calloc function processes a large size value that triggers the integer overflow, the resulting allocation of only one byte creates a dangerous situation where subsequent memory operations can lead to buffer overflows, heap corruption, or other memory safety violations. Attackers can exploit this weakness by carefully crafting input data that causes the allocation to overflow, thereby creating predictable memory layouts that can be leveraged for privilege escalation or arbitrary code execution. This vulnerability is particularly dangerous because it operates in a context-dependent manner, meaning that successful exploitation requires specific conditions related to the attacker's ability to control memory allocation parameters and system state. The attack surface is enhanced by the fact that this issue affects core system libraries that are heavily used across various applications and system components.
The security implications of CVE-2006-7252 align with several techniques documented in the MITRE ATT&CK framework, particularly those related to memory corruption attacks and privilege escalation. This vulnerability enables attackers to perform heap-based attacks that can be used to overwrite critical memory structures or execute malicious code in the context of the target process. The integer overflow condition creates a predictable failure mode that attackers can leverage to gain control over program execution flow, making it a valuable vector for exploitation. The vulnerability's classification as a memory allocation error places it within the broader category of software vulnerabilities that affect the foundational memory management capabilities of operating systems. This type of flaw can be particularly challenging to detect and remediate because it operates at a low level within the system's memory management infrastructure, affecting the fundamental assumptions about memory allocation size calculations that applications and system services rely upon.
Mitigation strategies for CVE-2006-7252 require immediate system updates and patches from the respective operating system vendors, as the vulnerability exists in core system libraries that cannot be easily bypassed through application-level code changes. Organizations should prioritize updating FreeBSD 6.4 and NetBSD systems to patched versions that address the integer overflow condition in the calloc implementation. Additionally, system administrators should implement memory allocation monitoring and anomaly detection mechanisms to identify unusual allocation patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of rigorous input validation and size checking in memory management functions, emphasizing the need for secure coding practices that prevent integer overflow conditions in system-level libraries. Network segmentation and privilege separation should also be implemented to limit the potential impact of successful exploitation attempts, while regular security audits of system libraries can help identify similar vulnerabilities in other components of the software stack.