CVE-2017-13833 in watchOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.13.1 is affected. The issue involves the "CFNetwork" component. It allows attackers to execute arbitrary code in a privileged context or cause a denial of service (memory corruption) via a crafted app.
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Analysis
by VulDB Data Team • 01/26/2021
The vulnerability identified as CVE-2017-13833 represents a critical security flaw within Apple's macOS operating system affecting versions prior to 10.13.1. This issue resides within the CFNetwork component, which serves as the core networking framework responsible for handling network communications and web services within the macOS ecosystem. The vulnerability stems from improper memory management within the network stack, creating a condition where maliciously crafted applications can exploit memory corruption patterns to gain elevated privileges or cause system instability.
The technical implementation of this vulnerability involves memory corruption within the CFNetwork framework's handling of network data structures. Attackers can craft specially designed applications that trigger buffer overflows or use-after-free conditions when the framework processes network requests. This memory corruption occurs during the parsing of network data, specifically when processing HTTP headers or other network protocol elements. The flaw enables attackers to manipulate memory addresses and execute arbitrary code with the privileges of the affected process, potentially allowing privilege escalation to system-level access. The vulnerability's classification aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write vulnerabilities, both of which are common in memory management flaws.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it provides attackers with the capability to execute code in a privileged context. This means that a malicious application could potentially gain root access or escalate privileges to perform actions such as modifying system files, installing malware, or accessing sensitive user data. The vulnerability's exploitation requires the user to install and run a crafted application, making it a user interaction-based attack vector. However, once executed, the privilege escalation could allow attackers to compromise the entire system. The attack surface includes any application that utilizes CFNetwork for internet connectivity, making it particularly dangerous as it affects core system functionality.
From a cybersecurity perspective, this vulnerability demonstrates the critical importance of network stack security in operating systems. The attack vector follows patterns consistent with the MITRE ATT&CK framework's privilege escalation techniques, specifically targeting system-level components to gain elevated access. Organizations should prioritize immediate patching of affected systems to mitigate this risk, as the vulnerability exists in the foundational networking libraries that support numerous applications and services. The fix implemented by Apple in macOS 10.13.1 involved memory validation checks and improved bounds checking within CFNetwork, addressing the underlying memory corruption patterns that enabled exploitation. Security teams should monitor for potential exploitation attempts and ensure all macOS systems are updated to versions that include the patched CFNetwork component to prevent successful exploitation attempts.