CVE-2019-8657 in iOS
Summary
by MITRE
An out-of-bounds read was addressed with improved input validation. This issue is fixed in iOS 12.4, macOS Mojave 10.14.6, tvOS 12.4, watchOS 5.3. Parsing a maliciously crafted office document may lead to an unexpected application termination or arbitrary code execution.
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Analysis
by VulDB Data Team • 11/07/2023
The vulnerability identified as CVE-2019-8657 represents a critical out-of-bounds read flaw that existed within Apple's Office document parsing libraries across multiple operating systems. This issue stems from insufficient input validation mechanisms when processing specially crafted office documents, creating a scenario where maliciously constructed file content could trigger memory access violations. The vulnerability affects iOS 12.4, macOS Mojave 10.14.6, tvOS 12.4, and watchOS 5.3, indicating the flaw was present across Apple's entire ecosystem of consumer and enterprise devices. The root cause of this vulnerability aligns with CWE-125, which specifically addresses out-of-bounds read conditions where programs access memory locations beyond the bounds of allocated buffers. This particular flaw demonstrates how seemingly benign document parsing operations can become attack vectors when proper boundary checks are absent.
The operational impact of CVE-2019-8657 extends beyond simple application crashes, presenting a potential path to arbitrary code execution that could be exploited by threat actors. When an attacker successfully crafts a malicious office document, the vulnerable parsing routines would attempt to read memory beyond intended boundaries, potentially causing applications to terminate unexpectedly or more dangerously, allowing attackers to inject and execute malicious code within the victim's system context. This vulnerability operates at the intersection of multiple ATT&CK techniques including initial access through malicious document delivery and execution through code injection methods. The flaw's exploitation potential increases significantly in enterprise environments where office documents are frequently shared and opened, making it a prime target for phishing campaigns and targeted attacks against organizational networks.
Apple's remediation approach for CVE-2019-8657 involved implementing enhanced input validation mechanisms that properly bounds check all memory accesses during document parsing operations. The fixes deployed across iOS 12.4, macOS Mojave 10.14.6, tvOS 12.4, and watchOS 5.3 demonstrate Apple's commitment to addressing memory safety issues through comprehensive patching of their core operating system components. Organizations should prioritize immediate deployment of these security updates to prevent exploitation attempts, as the vulnerability could be leveraged in sophisticated attack scenarios involving zero-day exploits. The mitigation strategy also includes user education regarding the dangers of opening untrusted office documents, combined with network-level security controls that can identify and block malicious file content before it reaches end-user systems. Security teams should monitor for indicators of compromise related to this vulnerability, particularly in environments where document sharing is prevalent, and consider implementing sandboxing technologies to limit the potential impact of successful exploitation attempts.