CVE-2018-1000035 in UnZIP
Summary
by MITRE
A heap-based buffer overflow exists in InfoZip UnZip version <= 6.00 in the processing of password-protected archives that allows an attacker to perform a denial of service or to possibly achieve code execution.
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Analysis
by VulDB Data Team • 02/06/2023
The vulnerability identified as CVE-2018-1000035 represents a critical heap-based buffer overflow in InfoZip UnZip version 6.00 and earlier, fundamentally compromising the integrity of the decompression process. This flaw specifically manifests during the handling of password-protected archive files, where the software fails to properly validate input lengths before performing memory allocations. The vulnerability stems from inadequate bounds checking within the archive processing logic, creating a scenario where maliciously crafted archive files can trigger unauthorized memory access patterns. Attackers exploiting this weakness can manipulate the heap memory structure through carefully constructed archive headers, potentially leading to arbitrary code execution or complete system denial of service.
The technical implementation of this vulnerability aligns with CWE-122, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent heap memory locations. The flaw occurs during the decompression phase when UnZip attempts to process encrypted archive entries, particularly affecting the password verification and decryption routines. The buffer overflow vulnerability specifically targets heap memory regions allocated for handling encrypted data structures, where the software does not properly validate the length of password strings or encrypted header data before copying them into fixed-size buffers. This oversight creates a predictable memory corruption pattern that can be systematically exploited by adversaries.
Operationally, this vulnerability presents significant risks to organizations relying on UnZip for archive management and file extraction processes. The potential for denial of service impacts extends beyond simple application crashes to include complete system instability when processing malicious archives in automated environments. Code execution capabilities further amplify the threat landscape, as attackers could leverage this vulnerability to deploy malicious payloads within systems that routinely process untrusted archive files. The vulnerability affects systems where UnZip is used as a command-line tool or integrated into larger applications, making it particularly dangerous in enterprise environments where automated file processing workflows are common. Network-based exploitation becomes possible when the vulnerable system processes archives received through email attachments, web downloads, or file transfer protocols.
Mitigation strategies should prioritize immediate patching of all affected UnZip installations to version 6.01 or later, which includes proper bounds checking mechanisms and heap memory management improvements. Organizations should implement strict file validation procedures for all archive processing workflows, including automated scanning of archive contents before decompression. Network segmentation and access controls should limit exposure of systems running UnZip to untrusted archive sources, while implementing sandboxed environments for archive processing tasks. Security monitoring should focus on detecting unusual file processing patterns or system resource consumption that may indicate exploitation attempts. The vulnerability demonstrates the importance of maintaining up-to-date software libraries and implementing comprehensive vulnerability management programs that include regular security assessments of third-party components. Additionally, system hardening measures such as stack canaries, address space layout randomization, and data execution prevention should be enabled to reduce the effectiveness of potential exploitation attempts.