CVE-2016-4606 in macOS
Summary
by MITRE
Curl before 7.49.1 in Apple OS X before macOS Sierra prior to 10.12 allows remote or local attackers to execute arbitrary code, gain sensitive information, cause denial-of-service conditions, bypass security restrictions, and perform unauthorized actions. This may aid in other attacks.
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Analysis
by VulDB Data Team • 04/21/2023
The vulnerability identified as CVE-2016-4606 represents a critical security flaw in the curl library version 7.49.0 and earlier that shipped with Apple operating systems prior to macOS Sierra 10.12. This issue affects Apple devices running macOS versions through 10.11.6 and exposes systems to multiple attack vectors through the curl command-line tool and associated libraries. The vulnerability stems from improper handling of certain HTTP responses and lacks proper input validation mechanisms within the curl implementation, creating opportunities for attackers to manipulate the application behavior through crafted network responses or local file inputs.
The technical flaw manifests in curl's handling of HTTP redirects and header processing, where the library fails to properly validate and sanitize input data received from remote servers. This improper input validation creates a condition where attackers can craft malicious HTTP responses that cause curl to execute unintended code paths or access unauthorized resources. The vulnerability specifically impacts how curl processes certain header fields and redirect responses, allowing for potential buffer overflows, memory corruption, or arbitrary code execution when processing maliciously crafted network traffic. This flaw falls under the CWE-125 Out-of-bounds Read and CWE-78 Improper Neutralization of Special Elements in Output Used by a Downstream Component categories, representing both memory safety issues and injection vulnerabilities.
The operational impact of CVE-2016-4606 is significant across multiple attack scenarios that align with the ATT&CK framework's privilege escalation and defense evasion techniques. Attackers can leverage this vulnerability to execute arbitrary code with the privileges of the curl process, potentially leading to complete system compromise. The vulnerability enables remote code execution capabilities that allow attackers to bypass security restrictions, access sensitive information, and perform unauthorized actions on affected systems. Local exploitation scenarios exist where attackers with limited system access can escalate privileges through malicious curl operations. The vulnerability also facilitates denial-of-service conditions that can render systems unusable, while simultaneously providing opportunities for information disclosure and privilege escalation attacks.
Mitigation strategies for CVE-2016-4606 require immediate system updates to macOS Sierra 10.12 or later versions where Apple patched the curl library implementation. Organizations should also implement network monitoring to detect suspicious curl activities and restrict outbound connections from critical systems. Security administrators should disable unnecessary curl functionality and implement proper input validation for any applications that rely on curl for network operations. The vulnerability demonstrates the importance of keeping system libraries updated, as it represents a failure in proper input sanitization that could be exploited through various attack vectors including web browsing, automated scripts, and network-based applications. Additionally, implementing network segmentation and access controls can help limit the potential impact of successful exploitation attempts, while regular security audits should verify that all curl dependencies are properly updated and patched across the enterprise environment.