CVE-2021-32263 in ok-file-formats
Summary
by MITRE • 08/25/2021
ok-file-formats through 2021-04-29 has a heap-based buffer overflow in the ok_csv_circular_buffer_read function in ok_csv.c.
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Analysis
by VulDB Data Team • 08/29/2021
The vulnerability identified as CVE-2021-32263 represents a critical heap-based buffer overflow within the ok-file-formats library, specifically affecting versions through 2021-04-29. This issue resides in the ok_csv_circular_buffer_read function located within the ok_csv.c source file, demonstrating a classic memory safety flaw that can lead to arbitrary code execution or system compromise. The vulnerability manifests when the library processes CSV data through circular buffer operations, creating an exploitable condition where input data can overflow allocated heap memory regions.
The technical flaw stems from inadequate bounds checking within the circular buffer implementation, allowing attackers to provide maliciously crafted CSV input that exceeds the allocated buffer size. This buffer overflow occurs during the read operation of the circular buffer, where the function fails to validate the amount of data being processed against the available buffer capacity. The heap-based nature of the vulnerability means that memory corruption occurs in dynamically allocated heap regions rather than stack-based buffers, making exploitation more complex but no less dangerous. This type of vulnerability falls under CWE-121, which describes heap-based buffer overflow conditions, and represents a direct violation of memory safety principles.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it creates potential for remote code execution when the affected library is used in applications processing untrusted CSV input. Systems utilizing ok-file-formats for CSV parsing operations become vulnerable to exploitation, particularly in environments where CSV files are received from external sources or user inputs. Attackers could leverage this vulnerability to execute arbitrary code on affected systems, potentially leading to complete system compromise, data exfiltration, or lateral movement within network environments. The vulnerability's presence in a widely-used file format processing library amplifies its impact across multiple application domains including web applications, data processing systems, and enterprise software platforms.
Mitigation strategies for CVE-2021-32263 should prioritize immediate patching of the ok-file-formats library to version 2021-05-01 or later, which contains the necessary fixes for the buffer overflow condition. Organizations should implement input validation measures to sanitize CSV data before processing, particularly when dealing with external or untrusted sources. Additionally, deployment of runtime protections such as address space layout randomization, stack canaries, and heap integrity checks can provide defense-in-depth measures against exploitation attempts. The vulnerability aligns with ATT&CK technique T1059.007, which covers scripting languages for execution, as attackers may leverage the buffer overflow to execute malicious payloads through compromised applications. System administrators should also monitor for indicators of compromise related to unauthorized code execution or unusual memory access patterns in systems processing CSV data. Regular security assessments and vulnerability scanning should be conducted to identify other potential instances of similar buffer overflow conditions within the application ecosystem, as the underlying memory safety issues may exist in other components of the software stack.