Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

News

4/19/2021
04:30 PM
50%
50%

Lazarus Group Uses New Tactic to Evade Detection

Attackers conceal malicious code within a BMP file to slip past security tools designed to detect embedded objects within images.

Security researchers with Malwarebytes have observed North Korea-affiliated advanced persistent threat actor Lazarus Group employing a new technique to deliver malware while evading security tools.

Related Content:

US Unseals Indictments Against North Korean Cyberattackers for Thefts Totaling $1.3B

Special Report: How Data Breaches Affect the Enterprise

New From The Edge: How to Create an Incident Response Plan From the Ground Up

Lazarus Group, an active and sophisticated group known for attacking targets around the world, recently expanded its primary mission beyond monetary theft to include stealing defense secrets. The group is known for developing custom malware families and using novel tactics.

One of its newest methods involves embedding a malicious HTML Application (HTA) file within a compressed zlib file, within a PNG file. During run time, the PNG file is converted into a BMP file format. Because the BMP file is uncompressed, converting from PNG to BMP automatically decompresses the malicious zlib object. Researchers call this a clever way to evade detection. Because the malicious object is compressed within the PNG image, it bypasses static detection.

This attack likely started with a phishing campaign in which emails arrives with a malicious file attached. When opened, the file prompts its viewer to enable macros. Doing this will lead to a message box; clicking this will load the final phishing lure — a participation form for a fair in a South Korean city. The document is weaponized with a macro that executes when it's opened.

While attribution is consistently a challenge in cyberattacks, the team found several signs that connect this activity with Lazarus Group, as outlined in a blog post on their findings.

"There are several similarities between this attack and past Lazarus operations and we believe these are strong indicators to attribute this attack to the Lazarus threat actor," writes Hossein Jazi, senior threat intelligence analyst.

Read the full blog post for more information.

Dark Reading's Quick Hits delivers a brief synopsis and summary of the significance of breaking news events. For more information from the original source of the news item, please follow the link provided in this article. View Full Bio

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
News
FluBot Malware's Rapid Spread May Soon Hit US Phones
Kelly Sheridan, Staff Editor, Dark Reading,  4/28/2021
Slideshows
7 Modern-Day Cybersecurity Realities
Steve Zurier, Contributing Writer,  4/30/2021
Commentary
How to Secure Employees' Home Wi-Fi Networks
Bert Kashyap, CEO and Co-Founder at SecureW2,  4/28/2021
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Current Issue
2021 Top Enterprise IT Trends
We've identified the key trends that are poised to impact the IT landscape in 2021. Find out why they're important and how they will affect you today!
Flash Poll
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2021-31755
PUBLISHED: 2021-05-07
An issue was discovered on Tenda AC11 devices with firmware through 02.03.01.104_CN. A stack buffer overflow vulnerability in /goform/setmac allows attackers to execute arbitrary code on the system via a crafted post request.
CVE-2021-31756
PUBLISHED: 2021-05-07
An issue was discovered on Tenda AC11 devices with firmware through 02.03.01.104_CN. A stack buffer overflow vulnerability in /gofrom/setwanType allows attackers to execute arbitrary code on the system via a crafted post request. This occurs when input vector controlled by malicious attack get copie...
CVE-2021-31757
PUBLISHED: 2021-05-07
An issue was discovered on Tenda AC11 devices with firmware through 02.03.01.104_CN. A stack buffer overflow vulnerability in /goform/setVLAN allows attackers to execute arbitrary code on the system via a crafted post request.
CVE-2021-31758
PUBLISHED: 2021-05-07
An issue was discovered on Tenda AC11 devices with firmware through 02.03.01.104_CN. A stack buffer overflow vulnerability in /goform/setportList allows attackers to execute arbitrary code on the system via a crafted post request.
CVE-2021-31458
PUBLISHED: 2021-05-07
This vulnerability allows remote attackers to execute arbitrary code on affected installations of Foxit Reader 10.1.1.37576. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the handlin...