CVE-2007-4268 in Mac OS X
Summary
by MITRE
Integer signedness error in the Networking component in Apple Mac OS X 10.4 through 10.4.10 allows local users to execute arbitrary code via a crafted AppleTalk message with a negative value, which satisfies a signed comparison during mbuf allocation but is later interpreted as an unsigned value, which triggers a heap-based buffer overflow.
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Analysis
by VulDB Data Team • 06/07/2025
The vulnerability described in CVE-2007-4268 represents a critical integer signedness error within the Apple Mac OS X networking stack that affects versions 10.4 through 10.4.10. This flaw resides in the AppleTalk protocol implementation where a negative integer value is processed through a signed comparison during memory buffer allocation. The vulnerability stems from a fundamental mismatch in how signed and unsigned integer values are handled within the system's memory management routines. During the mbuf allocation process, the system performs a signed comparison that accepts negative values, but these same values are later interpreted as unsigned integers, creating a condition where the system allocates insufficient memory for the actual data size.
The technical exploitation of this vulnerability occurs when a local attacker crafts a malicious AppleTalk message containing a negative value that passes the initial signed comparison check. This allows the system to allocate memory based on the negative value, which when later interpreted as unsigned, results in a much larger memory allocation request than intended. The heap-based buffer overflow occurs because the system allocates memory for a smaller buffer than what is actually needed to accommodate the data, creating a situation where subsequent data writes overflow into adjacent memory regions. This type of vulnerability falls under CWE-190, which specifically addresses integer overflow and underflow conditions, and more precisely maps to CWE-191, which deals with integer underflow. The underlying issue demonstrates poor input validation and improper handling of signed versus unsigned integer arithmetic.
The operational impact of this vulnerability is severe as it allows local users to execute arbitrary code with system-level privileges, effectively bypassing the security model of the operating system. The heap-based buffer overflow creates opportunities for memory corruption that can be leveraged to overwrite critical system data structures, function pointers, or return addresses within the execution stack. Attackers can exploit this condition to gain elevated privileges and potentially compromise the entire system. The vulnerability's local nature means that exploitation requires physical access or the ability to execute code on the target system, but the privilege escalation potential makes it particularly dangerous. From an attacker's perspective, this aligns with ATT&CK technique T1068, which involves local privilege escalation through system vulnerabilities, and T1059, which covers the execution of malicious code through system interfaces.
Mitigation strategies for this vulnerability include applying the official security patches released by Apple that correct the integer signedness handling in the AppleTalk protocol implementation. System administrators should ensure that all Mac OS X systems are updated to versions 10.4.11 or later where this vulnerability has been addressed through proper integer validation and signedness conversion. Additionally, network administrators can implement network segmentation to isolate AppleTalk traffic and disable AppleTalk protocols on systems where they are not required. The fix typically involves ensuring that values are properly validated before being used in memory allocation calculations and that signed integers are converted to unsigned values before being used in unsigned contexts. Security monitoring should include detection of unusual AppleTalk traffic patterns and memory allocation anomalies that might indicate exploitation attempts.