CVE-2017-7123 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.13 is affected. The issue involves the third-party "file" product. Versions before 5.30 allow remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact.
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Analysis
by VulDB Data Team • 01/20/2021
The vulnerability identified as CVE-2017-7123 represents a critical security flaw within Apple's macOS ecosystem that affected versions prior to 10.13. This issue specifically targets the third-party file utility product, which serves as a fundamental component for file type detection and identification across various operating systems. The vulnerability stems from improper handling of crafted input data within the file command's parsing mechanisms, creating a potential attack surface that could be exploited by remote threat actors. The affected file utility version 5.29 and earlier contains a buffer over-read condition that manifests when processing malformed file signatures or corrupted data structures. This flaw operates at the core of how the system identifies and categorizes file types, making it particularly dangerous as it could be triggered through routine file operations or when processing untrusted input from network sources. The vulnerability's impact extends beyond simple denial of service as it may potentially allow for arbitrary code execution or information disclosure depending on the specific attack vector employed.
The technical implementation of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions in software systems, and represents a classic buffer over-read scenario where the application attempts to access memory beyond the allocated buffer boundaries. This particular flaw demonstrates how third-party utilities integrated into operating systems can introduce significant security risks when proper input validation and memory management practices are not implemented. The attack surface becomes particularly concerning when considering that the file utility is invoked automatically by many system components during file processing operations, including web browsers, email clients, and file managers. The vulnerability operates through a specific pattern where crafted file headers or metadata structures trigger the buffer over-read condition, causing the application to crash or potentially execute unintended code paths. This behavior creates a pathway for attackers to manipulate the system's file identification processes and potentially escalate privileges or gain unauthorized access to system resources.
The operational impact of CVE-2017-7123 extends far beyond simple system instability, as it represents a foundational security weakness that could enable more sophisticated attacks within the macOS environment. Organizations relying on older macOS versions would face significant risk exposure, particularly in enterprise settings where automated file processing and network-based file operations are common. The vulnerability's potential for unspecified other impacts, as noted in the original description, suggests that attackers might be able to leverage this flaw for more advanced exploitation techniques beyond simple denial of service. This includes potential privilege escalation attacks that could allow adversaries to execute malicious code with elevated system privileges, or information disclosure attacks that could reveal sensitive system data. The widespread use of the file utility across various system components means that a successful exploitation could affect multiple applications and services simultaneously, creating cascading failures throughout the system. Security professionals must consider this vulnerability as part of broader attack chains that could lead to complete system compromise, particularly when combined with other vulnerabilities or social engineering techniques.
Mitigation strategies for CVE-2017-7123 primarily focus on immediate system updates and operational security measures to protect against exploitation. The most effective approach involves upgrading affected macOS systems to version 10.13 or later, which includes patched versions of the vulnerable file utility component. Organizations should implement comprehensive patch management processes that prioritize this vulnerability due to its potential for privilege escalation and system compromise. Network administrators should consider implementing additional security controls such as sandboxing mechanisms for file processing operations and monitoring for unusual file identification patterns that might indicate exploitation attempts. The vulnerability's characteristics make it particularly suitable for exploitation through web-based attack vectors, so browser security measures including content filtering and sandboxing should be enhanced. System administrators should also consider implementing file integrity monitoring solutions that can detect unauthorized modifications to the file utility or related system components. From an att&ck framework perspective, this vulnerability maps to techniques involving privilege escalation and defense evasion, making it particularly dangerous when combined with other attack methodologies. Organizations should also consider implementing network segmentation to limit the potential impact of successful exploitation and establish incident response procedures specifically addressing this type of buffer over-read vulnerability.