Security Experts:

Connect with us

Hi, what are you looking for?

SecurityWeekSecurityWeek

Malware & Threats

WinRAR Vulnerability Exposes Millions of Users to Attacks

WinRAR, the popular data compression tool utilized by over 500 million users worldwide, is affected by a serious vulnerability that can allow arbitrary code execution through specially crafted ACE archives.

WinRAR, the popular data compression tool utilized by over 500 million users worldwide, is affected by a serious vulnerability that can allow arbitrary code execution through specially crafted ACE archives.

Tests conducted by researchers at Check Point Software Technologies using the WinAFL fuzzer led to the discovery of a security bug in the unacev2.dll library used by WinRAR for unpacking ACE archives.

The library is affected by a flaw (CVE-2018-20250) that can allow malicious actors to create an ACE archive that extracts files to an arbitrary folder on the system.

Check Point researchers have demonstrated that the security hole can be exploited to extract a harmless file to the destination folder selected by the user, while also extracting a malicious file to a location specified by the attacker. The attacker could, for example, extract a piece of malware to the Windows Startup folder and it would get executed the next time the operating system boots.

The cybersecurity firm reported its findings to WinRAR developer RARLab, which decided that the best way to protect users against potential attacks is to remove support for ACE archives. This decision has been implemented starting with the release of WinRAR 5.70 beta 1.

RARLab says unacev2.dll has not been updated since 2005 and the company no longer has access to its source code.

The following CVE identifiers have been assigned to other WinRAR vulnerabilities found by Check Point during its fuzzing project: CVE-2018-20251, CVE-2018-20252 and CVE-2018-20253. The company has published technical details and a video showing an exploit in action.

The popularity of WinRAR can make it a tempting target for attackers. While no WinRAR vulnerabilities have been disclosed in the past three years, a flaw in the archiving tool was exploited in cyber espionage campaigns back in 2014.

WinRAR vulnerabilities are still valuable. Exploit acquisition firm Zerodium offers up to $80,000 for remote code execution flaws and at one point last year it offered as much as $100,000.

Related: Critical Vulnerability Addressed in Popular Code Libraries

Related: Microsoft Patches Code Execution Vulnerability in wimgapi Library

Related: CTB-Locker Ransomware Impersonator Uses WinRAR for Encryption

Written By

Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.

Click to comment

Expert Insights

Related Content

Malware & Threats

Microsoft plans to improve the protection of Office users by blocking XLL add-ins from the internet.

Mobile & Wireless

Technical details published for an Arm Mali GPU flaw leading to arbitrary kernel code execution and root on Pixel 6.

Cloud Security

VMware vRealize Log Insight vulnerability allows an unauthenticated attacker to take full control of a target system.

Mobile & Wireless

Apple rolled out iOS 16.3 and macOS Ventura 13.2 to cover serious security vulnerabilities.

Mobile & Wireless

Apple’s iOS 12.5.7 update patches CVE-2022-42856, an actively exploited vulnerability, in old iPhones and iPads.

Vulnerabilities

Security researchers have observed an uptick in attacks targeting CVE-2021-35394, an RCE vulnerability in Realtek Jungle SDK.

Vulnerabilities

Google has awarded more than $25,000 to the researchers who reported the vulnerabilities patched with the release of the latest Chrome update.

Mobile & Wireless

Two vulnerabilities in Samsung’s Galaxy Store that could be exploited to install applications or execute JavaScript code by launching a web page.