CVE-2020-11528 in bit2spr
Summary
by MITRE
bit2spr 1992-06-07 has a stack-based buffer overflow (129-byte write) in conv_bitmap in bit2spr.c via a long line in a bitmap file.
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Analysis
by VulDB Data Team • 05/17/2024
The vulnerability identified as CVE-2020-11528 represents a critical stack-based buffer overflow flaw in the bit2spr utility version 1992-06-07. This issue manifests within the conv_bitmap function located in the bit2spr.c source file, where the software fails to properly validate input data length during bitmap file processing. The specific flaw occurs when the application encounters a bitmap file containing an excessively long line, leading to a 129-byte write operation that exceeds the allocated stack buffer boundaries. This vulnerability falls under the Common Weakness Enumeration category CWE-121, which specifically addresses stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent stack memory locations.
The operational impact of this vulnerability extends beyond simple memory corruption, as it creates potential pathways for arbitrary code execution within the context of the running process. When an attacker successfully triggers this buffer overflow, they can manipulate the stack pointer and return addresses, potentially allowing for privilege escalation or complete system compromise. The vulnerability demonstrates characteristics consistent with the attack pattern described in MITRE ATT&CK technique T1059.007 for command and script injection, as the overflow could enable attackers to inject malicious code into the application's execution flow. The stack-based nature of the vulnerability means that the attack surface is particularly concerning since stack memory contains critical execution context including return addresses, saved registers, and local variables that maintain program state.
The exploitation of this vulnerability requires a carefully crafted malicious bitmap file that contains a line exceeding the buffer capacity, triggering the overflow during the conversion process. The bit2spr utility, designed for bitmap format conversion, becomes an attractive target for attackers seeking to leverage this flaw in environments where such utilities process untrusted input from external sources. Security practitioners should note that this vulnerability represents a classic example of insufficient input validation in legacy software, where modern security practices were not fully implemented during the original development cycle. The vulnerability's persistence in this older version highlights the importance of regular security assessments and patch management, particularly for widely deployed utilities that handle file format conversions. Organizations using this software should immediately implement mitigations including input validation controls, address space layout randomization, and stack canaries to reduce the exploitability of this vulnerability. The issue also underscores the necessity of following secure coding practices such as those outlined in the CERT Secure Coding Standards, specifically the recommendations for buffer overflow prevention and proper bounds checking in input processing functions.