CVE-2019-8722 in Xcode
Summary
by MITRE
Multiple issues in ld64 in the Xcode toolchains were addressed by updating to version ld64-507.4. This issue is fixed in Xcode 11.0. Compiling code without proper input validation could lead to arbitrary code execution with user privilege.
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Analysis
by VulDB Data Team • 09/09/2020
The vulnerability identified as CVE-2019-8722 represents a critical security flaw within the ld64 linker component of Apple's Xcode development toolchain. This issue affects the linker's handling of input validation during code compilation processes, creating potential pathways for malicious code execution. The vulnerability was specifically addressed through an update to ld64 version 507.4 and subsequently resolved in Xcode 11.0, demonstrating the severity of the flaw that required immediate attention from developers and system administrators.
The technical nature of this vulnerability stems from insufficient input validation mechanisms within the ld64 linker utility, which is responsible for combining object files into executable binaries during the compilation process. When developers compile code using affected Xcode versions, the linker fails to properly validate certain input parameters, creating opportunities for attackers to inject malicious code that could be executed with the privileges of the user running the compilation process. This flaw operates at the intersection of software compilation and privilege escalation, making it particularly dangerous in development environments where users often possess elevated system privileges.
From an operational impact perspective, this vulnerability presents significant risks to software development environments, particularly those where untrusted code is compiled or where developers work with potentially malicious input. The arbitrary code execution capability allows attackers to gain control over systems running affected toolchains, potentially leading to complete system compromise. The vulnerability is especially concerning in enterprise environments where development teams may be working with code from multiple sources or where automated build processes could be exploited. Security professionals should note that this issue aligns with CWE-121, which addresses stack-based buffer overflow conditions, and may also relate to CWE-78, which covers OS command injection vulnerabilities, depending on the specific exploitation vectors.
Organizations should prioritize immediate remediation by upgrading to Xcode 11.0 or later versions that include the patched ld64 component. System administrators should also implement additional security controls such as code review processes, input validation testing, and restricted compilation environments to mitigate potential exploitation attempts. The ATT&CK framework categorizes this vulnerability under the T1059.001 technique for command and scripting interpreter, as the arbitrary code execution could be achieved through malicious command injection in the compilation process. Regular security assessments of development toolchains and maintaining updated software versions remain critical defensive measures against similar vulnerabilities in the broader software supply chain.