CVE-2018-6758 in uWSGI
Summary
by MITRE
The uwsgi_expand_path function in core/utils.c in Unbit uWSGI through 2.0.15 has a stack-based buffer overflow via a large directory length.
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Analysis
by VulDB Data Team • 02/03/2023
The vulnerability identified as CVE-2018-6758 resides within the uWSGI application server software developed by Unbit, specifically affecting versions through 2.0.15. This flaw manifests in the uwsgi_expand_path function located in the core/utils.c source file, representing a critical security weakness that can be exploited to compromise system integrity. The vulnerability stems from inadequate input validation and memory management practices within the path expansion functionality that uWSGI employs to process directory references and file paths.
The technical implementation of this stack-based buffer overflow occurs when the uwsgi_expand_path function processes directory paths that exceed predetermined buffer size limits. When a maliciously crafted directory name or path length surpasses the allocated stack buffer space, the function fails to properly bounds-check the input data before copying it into memory. This condition creates a scenario where adjacent memory locations can be overwritten with attacker-controlled data, potentially leading to arbitrary code execution or application crash. The vulnerability follows the common pattern of stack buffer overflow attacks where insufficient input validation allows for memory corruption that can be leveraged by adversaries to gain unauthorized system access.
Operationally, this vulnerability presents significant risks to systems running affected uWSGI versions, particularly in web server environments where uWSGI serves as a crucial component for handling HTTP requests and application processing. Attackers could exploit this weakness by crafting malicious requests that include excessively long directory paths, potentially leading to complete system compromise. The impact extends beyond simple denial of service, as successful exploitation could allow attackers to execute arbitrary code with the privileges of the uWSGI process, which typically runs with elevated permissions. This makes the vulnerability particularly dangerous in production environments where uWSGI handles sensitive data processing and web application serving functions.
Mitigation strategies for CVE-2018-6758 should prioritize immediate patching of affected uWSGI installations to version 2.0.16 or later, which contains the necessary fixes for the buffer overflow condition. Organizations should also implement network-level controls such as input validation firewalls and web application firewalls to filter out suspicious path requests before they reach the uWSGI server. Additionally, system administrators should consider implementing process isolation techniques and privilege separation to limit the potential impact of successful exploitation. The vulnerability aligns with CWE-121 stack-based buffer overflow classification and could be mapped to ATT&CK technique T1059.007 for command and script injection, as exploitation may involve executing malicious code through compromised uWSGI processes. Regular security auditing and input validation testing should be implemented to prevent similar vulnerabilities from emerging in other components of the uWSGI ecosystem.