CVE-2015-5897 in Mac OS X
Summary
by MITRE
The Address Book framework in Apple OS X before 10.11 allows local users to gain privileges by using an environment variable to inject code into processes that rely on this framework.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 06/20/2022
The vulnerability identified as CVE-2015-5897 represents a privilege escalation flaw within Apple's Address Book framework affecting macOS versions prior to 10.11. This issue stems from improper handling of environment variables during process execution, creating a path for local attackers to inject malicious code into processes that utilize the framework. The vulnerability exists at the system level where the framework fails to properly sanitize or validate environment variables, allowing attackers to manipulate the execution flow of legitimate applications. The flaw specifically impacts processes that depend on the Address Book framework, which is commonly used by various system applications and third-party software for contact management and address handling operations. This creates a significant attack surface where malicious code injection can occur without requiring elevated privileges initially, potentially enabling attackers to escalate their privileges to system-level access.
The technical implementation of this vulnerability leverages environment variable manipulation to achieve code injection within processes that utilize the Address Book framework. When applications execute and rely on this framework, they inherit environment variables from their execution context, including variables that may contain paths or references to libraries. Attackers can exploit this by setting specific environment variables that point to malicious libraries or code, which then gets loaded and executed by processes using the vulnerable framework. This type of vulnerability falls under the category of environment variable injection attacks and is classified as CWE-74 according to the Common Weakness Enumeration catalog. The vulnerability demonstrates a classic case of insecure environment handling where the system does not properly validate or sanitize the contents of environment variables before passing them to framework functions. This weakness enables attackers to influence the dynamic linking behavior of applications, effectively allowing them to execute arbitrary code within the context of the targeted process.
The operational impact of CVE-2015-5897 extends beyond simple code injection capabilities to encompass full privilege escalation potential within the macOS environment. Local attackers who can manipulate environment variables can leverage this vulnerability to execute malicious code with the privileges of the targeted process, which often includes system-level access. This presents a serious threat to system integrity and confidentiality, as attackers can potentially access sensitive information, modify system files, or establish persistent access to the compromised system. The vulnerability is particularly concerning because it requires minimal privileges to exploit and can be used to bypass standard security controls. In practical attack scenarios, this vulnerability could enable attackers to compromise user accounts, install backdoors, or perform other malicious activities that would otherwise require more sophisticated attack vectors. The impact is further amplified because many system applications rely on the Address Book framework, increasing the potential attack surface and the number of vulnerable processes that can be targeted.
Mitigation strategies for CVE-2015-5897 focus on both immediate remediation and long-term security hardening approaches. The primary and most effective mitigation is to upgrade to macOS 10.11 or later versions where Apple has addressed this vulnerability through proper environment variable sanitization and framework security improvements. System administrators should also implement environment variable restriction policies that limit the ability of untrusted code to manipulate critical environment variables. Additionally, organizations should conduct regular security audits to identify applications that may still be vulnerable to similar environment injection attacks. The vulnerability highlights the importance of following secure coding practices, particularly around environment variable handling and dynamic library loading, which aligns with ATT&CK technique T1059.001 for command and scripting interpreter execution. Security teams should also implement monitoring solutions that can detect unusual environment variable modifications or unexpected code loading patterns that may indicate exploitation attempts. Regular patch management processes should be maintained to ensure that all system components remain up-to-date with the latest security fixes, as this vulnerability demonstrates how seemingly minor framework issues can lead to significant security implications.