Multiple Vulnerabilities in 7-Zip Could Allow for Arbitrary Code Execution

ITS Advisory Number: 
2018-009
Date(s) Issued: 
Thursday, January 25, 2018
Subject: 
Multiple Vulnerabilities in 7-Zip Could Allow for Arbitrary Code Execution
Overview: 

Multiple vulnerabilities have been discovered in 7-Zip, the most severe of which could allow for arbitrary code execution. 7-Zip is a free and open-source file archiver. Successful exploitation of the most severe of these vulnerabilities could allow for arbitrary code execution. Depending on the privileges associated with the user, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than those who operate with administrative user rights.

Systems Affected: 
  • 7-Zip versions prior to 18.00
RISK
GOVERNMENT
Large and medium government entities: 
High
Small government entities: 
High
BUSINESS
Large and medium business entities: 
High
Small business entities: 
High
Home Users: 
High
Description: 

Multiple vulnerabilities have been discovered in 7-Zip, the most severe of which could allow for arbitrary code execution. Details of these vulnerabilities are as follows:

  • Improper exception handling in 7-Zip’s RAR3 handler can cause heap or stack memory corruptions. (CVE-2018-5996)
  • A heap buffer overflow vulnerability in 7-Zip’s shrink decoder. (CVE-2017-17969)

Successful exploitation of the most severe of these vulnerabilities could allow for arbitrary code execution. Depending on the privileges associated with the user, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than those who operate with administrative user rights.

Actions: 
  • After appropriate testing, immediately apply appropriate updates provided by 7-Zip to vulnerable systems.
  • Run all software as a non-privileged user (one without administrative privileges) to diminish the effects of a successful attack.
  • Apply the Principle of Least Privilege to all systems and services.