CVE-2018-10115 in 7-zip
Summary
by MITRE
Incorrect initialization logic of RAR decoder objects in 7-Zip 18.03 and before can lead to usage of uninitialized memory, allowing remote attackers to cause a denial of service (segmentation fault) or execute arbitrary code via a crafted RAR archive.
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Analysis
by VulDB Data Team • 02/02/2020
The vulnerability identified as CVE-2018-10115 represents a critical memory safety issue within the 7-Zip archive extraction utility affecting versions 18.03 and earlier. This flaw manifests in the RAR decoder component where improper initialization of decoder objects creates conditions for uninitialized memory access during archive processing. The vulnerability stems from inadequate validation and initialization routines that fail to properly set up internal data structures before they are utilized in decompression operations. Attackers can exploit this weakness by crafting specially designed RAR archives that trigger the flawed initialization path when processed by vulnerable 7-Zip versions.
The technical implementation of this vulnerability operates through a classic uninitialized memory access pattern that aligns with CWE-457, which describes the use of uninitialized variables in software systems. When the RAR decoder attempts to process maliciously constructed archive files, the uninitialized memory regions contain unpredictable data that can lead to erratic program behavior. The decoder objects fail to properly initialize their internal state variables before being used in decompression algorithms, creating a scenario where memory addresses may contain arbitrary values that influence program execution flow. This improper initialization creates a potential code execution vector that can be leveraged to trigger segmentation faults or more dangerous arbitrary code execution depending on the specific memory conditions encountered during processing.
The operational impact of CVE-2018-10115 extends beyond simple denial of service scenarios to encompass potential remote code execution capabilities that make it particularly dangerous in enterprise environments. Systems running vulnerable 7-Zip versions are at risk when processing untrusted archive files, whether through automated extraction processes, user downloads, or email attachments. The vulnerability can be exploited through various attack vectors including web-based file processing, automated archive extraction services, or any scenario where 7-Zip is used to decompress user-supplied RAR files. Network-based attacks can be particularly effective as attackers can craft malicious archives that will trigger the vulnerability when processed by vulnerable systems, potentially leading to complete system compromise depending on the execution context.
Organizations should implement immediate mitigation strategies including upgrading to 7-Zip version 18.05 or later where this vulnerability has been resolved through proper initialization of decoder objects. System administrators should also consider implementing network-level controls to prevent processing of untrusted archive files, particularly those with RAR extensions, until full patch deployment is complete. The ATT&CK framework categorizes this vulnerability under T1203, which describes exploitation of software vulnerabilities for privilege escalation and code execution. Security teams should monitor for potential exploitation attempts through network traffic analysis and file processing logs to detect malicious archive handling activities. Additionally, implementing sandboxed environments for archive processing and regular security assessments of archive handling components can help reduce the attack surface while patches are deployed across the organization.