CVE-2016-1826

Vulnerability

An integer overflow vulnerability exists in the dtrace implementation within the XNU kernel of Apple OS X. The flaw occurs when the kernel fails to properly validate user-supplied chunk size values, leading to a memory corruption issue. This affects OS X El Capitan versions prior to 10.11.5. The vulnerability is identified as CVE-2016-1826 and was addressed in the OS X El Capitan v10.11.5 security update [1][2].

Exploitation

Exploitation requires local access to the system and user interaction, such as visiting a malicious webpage or opening a crafted file. The attacker must trigger the vulnerable code path in dtrace by supplying a specially crafted chunk size that causes an integer overflow. This leads to arbitrary read and write of kernel memory, enabling privilege escalation [2].

Impact

Successful exploitation allows an attacker to execute arbitrary code with kernel privileges, resulting in full compromise of the affected system. The attacker gains the ability to read, modify, or destroy sensitive data, install malware, and perform other actions at the highest privilege level [1][2].

Mitigation

Apple released OS X El Capitan v10.11.5 on May 18, 2016, which includes a fix for this vulnerability. Users should update to this version or later. No workarounds are documented. The vulnerability is not listed in CISA's Known Exploited Vulnerabilities (KEV) catalog [1].