CVE-2016-8619 in macOS
Summary
by MITRE
The function `read_data()` in security.c in curl before version 7.51.0 is vulnerable to memory double free.
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Analysis
by VulDB Data Team • 10/07/2022
The vulnerability identified as CVE-2016-8619 represents a critical memory safety issue within the curl library's security.c file, specifically affecting versions prior to 7.51.0. This flaw manifests in the read_data() function where improper memory management leads to a double free condition that can be exploited by malicious actors. The vulnerability stems from the improper handling of dynamically allocated memory blocks within the function's execution flow, creating opportunities for memory corruption that could be leveraged for arbitrary code execution or denial of service attacks.
The technical implementation of this vulnerability involves a scenario where the read_data() function in curl's security.c file allocates memory for data processing operations and subsequently frees it without proper validation of the memory state. When the function encounters certain input conditions or processing paths, it may attempt to free the same memory block twice, leading to a double free condition. This memory management error occurs because the function does not properly track memory allocation status or validate whether memory has already been freed before attempting additional deallocation operations. Such conditions are particularly dangerous in network security applications like curl where input data can be manipulated by remote attackers.
The operational impact of CVE-2016-8619 extends beyond simple memory corruption, as it creates potential attack vectors that align with several ATT&CK techniques including privilege escalation through memory corruption and execution of malicious code via application vulnerabilities. The vulnerability affects curl's ability to securely process network data, making it susceptible to exploitation in scenarios involving HTTP, HTTPS, or other protocols that rely on curl's underlying security mechanisms. Systems utilizing vulnerable curl versions in web applications, automated scripts, or security tools become at risk of being compromised through memory corruption attacks that could lead to complete system compromise or service disruption.
This vulnerability is classified under CWE-415 as an improper cleanup of memory, specifically highlighting the double free condition that occurs when memory is freed twice. The issue demonstrates the importance of proper memory management in security-critical applications and underscores the need for comprehensive input validation and memory state tracking. Organizations using curl versions before 7.51.0 should prioritize immediate patching, as the vulnerability creates opportunities for attackers to manipulate memory structures and potentially execute arbitrary code. The remediation process involves upgrading to curl version 7.51.0 or later, which includes proper memory management fixes that prevent the double free condition from occurring during read_data() function execution.
Security implementations relying on curl for network communications, including web scraping tools, automated security scanning applications, and network monitoring systems, must ensure proper version compliance to mitigate this risk. The vulnerability represents a fundamental flaw in memory management practices that could be exploited in various attack scenarios, making it essential for security teams to conduct comprehensive vulnerability assessments and ensure all curl installations are updated to patched versions. Organizations should also implement monitoring for unusual memory allocation patterns and consider additional defensive measures such as address space layout randomization and stack canaries to further protect against exploitation of similar memory corruption vulnerabilities.