CVE-2021-32281 in Gravity
Summary
by MITRE • 09/20/2021
An issue was discovered in gravity through 0.8.1. A heap-buffer-overflow exists in the function gnode_function_add_upvalue located in gravity_ast.c. It allows an attacker to cause code Execution.
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Analysis
by VulDB Data Team • 09/29/2021
The vulnerability identified as CVE-2021-32281 represents a critical heap-buffer-overflow condition within the gravity programming language interpreter version 0.8.1 and earlier. This flaw exists in the gnode_function_add_upvalue function located in the gravity_ast.c source file, which forms a core component of the interpreter's abstract syntax tree processing functionality. The heap-buffer-overflow occurs when the interpreter processes certain malformed input code that triggers improper memory allocation and handling during function upvalue processing, creating a scenario where attacker-controlled data can overwrite adjacent memory regions.
The technical nature of this vulnerability stems from inadequate bounds checking within the memory management routines of the gravity interpreter. When the interpreter encounters specific code patterns that involve function upvalues, it fails to properly validate the size of memory allocations before writing data to heap-allocated buffers. This oversight allows an attacker to craft malicious code that, when executed by the gravity interpreter, can cause the program to write beyond the allocated buffer boundaries. The vulnerability is classified as a heap-based buffer overflow according to CWE-122, which specifically addresses insufficient restriction of operations within the bounds of a memory buffer.
The operational impact of this vulnerability is severe and directly translates to remote code execution capabilities for attackers. Since the gravity interpreter is designed to execute user-provided code, an attacker who can inject malicious code into a system running gravity can leverage this vulnerability to execute arbitrary commands on the target system. The attack surface expands significantly when considering that gravity is often used in web applications and server-side environments where user input is processed through the interpreter. This vulnerability can be exploited through various attack vectors including but not limited to web application input fields, file uploads, or any mechanism that allows untrusted code execution within the gravity environment. The exploitability of this vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, specifically targeting the gravity interpreter as a means of achieving code execution.
Mitigation strategies for CVE-2021-32281 should prioritize immediate patching of the gravity interpreter to version 0.8.2 or later, which contains the necessary fixes for the heap-buffer-overflow condition. Organizations should implement comprehensive input validation and sanitization measures to prevent malicious code injection into systems running gravity interpreters. Additionally, deployment of memory protection mechanisms such as stack canaries, address space layout randomization, and heap protection features can provide additional defense-in-depth layers. Network segmentation and access controls should be implemented to limit exposure of systems running gravity interpreters to untrusted users or external networks. Regular security audits and code reviews focusing on memory management practices should be conducted to identify similar vulnerabilities in other components of the software ecosystem. The vulnerability also highlights the importance of following secure coding practices and adhering to industry standards such as the CWE guidelines for buffer overflow prevention and the OWASP Top Ten security principles for preventing code execution vulnerabilities in interpreted languages.