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.

Attacks/Breaches

10/24/2016
05:15 PM
Connect Directly
Twitter
LinkedIn
RSS
E-Mail
50%
50%

New Kovter Trojan Variant Spreading Via Targeted Email Campaign

The authors of a malware sample that has been around for more than two years have yet another trick for distributing it.

The Kovter malware sample that has infected systems around the world for the past couple of years is proving to be a case study in how threat actors constantly tweak their malware to keep one step ahead of the defenders.

Trojan Kovter surfaced about two years ago as a screenlocker and scareware sample masquerading as a law enforcement tool. Since then it has been used in click-fraud and malvertising campaigns, as data-encrypting ransomware, and a malware installation tool.

Kovter’s authors have used a variety of ways to distribute the malware, to avoid detection, and to gain persistence on infected systems. For instance, Kovter is among the first file-less malware tools that resides only in memory and runs from the system registry rather than the disk to evade detection by file-based malware detection products. It also has been seen masquerading as Firefox and Chrome updates and as a JavaScript downloader.

This week, security firm Morphisec reported yet another tweak to the malicious software.  Over a period of four days last week, Morphisec said it identified multiple malicious macro-based documents delivering Kovter via targeted emails.

“Compared to the previous wave in July-August, where it was delivered as Chrome or Firefox update or as a zip file, this time it came as a macro with click-based activation documents,” says Michael Gorelik, vice presient of research and development at Morphisec.  “It was not enough to enable the macro content, the user needed to also click on the image inside the macro,” Gorelik said of a Kovter sample recovered from one of the company’s customers.

The new approach allows the malware to bypass security sandbox approaches that are based entirely on macro enablement alone. The macro writers also added a restriction password on image edit to prevent the sandbox from automatically mapping the macro procedures to be activated, Gorelik said in a technical analysis of the malware.

The modified macro with the click-based execution is not the only feature that’s new in the Kovter sample that Morphisec analyzed last week. In the latest attack, the threat actors behind the campaign also used highly targeted emails to try and lure users into interacting with the macro.

Examples of the targeting included the threat actors approaching potential victims using their actual names, job titles, and company names, Gorelik says.

“Monitoring the latest campaigns, we found the often-used 'invoice/bill' email pattern,” he said in the technical analysis of the malware.

The subject and content in many of the targeted emails purport to inform the victim about an invoice that is due or a payment that needs immediate attention. As with many spear-phishing campaigns, the content in the emails is designed to convey a sense of urgency and threats of dire consequences for failure to act.

Related stories

 

Jai Vijayan is a seasoned technology reporter with over 20 years of experience in IT trade journalism. He was most recently a Senior Editor at Computerworld, where he covered information security and data privacy issues for the publication. Over the course of his 20-year ... View Full Bio
 

Recommended Reading:

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
Overcoming the Challenge of Shorter Certificate Lifespans
Mike Cooper, Founder & CEO of Revocent,  10/15/2020
US Counterintelligence Director & Fmr. Europol Leader Talk Election Security
Kelly Sheridan, Staff Editor, Dark Reading,  10/16/2020
7 Tips for Choosing Security Metrics That Matter
Ericka Chickowski, Contributing Writer,  10/19/2020
Register for Dark Reading Newsletters
White Papers
Video
Cartoon
Current Issue
Special Report: Computing's New Normal
This special report examines how IT security organizations have adapted to the "new normal" of computing and what the long-term effects will be. Read it and get a unique set of perspectives on issues ranging from new threats & vulnerabilities as a result of remote working to how enterprise security strategy will be affected long term.
Flash Poll
How IT Security Organizations are Attacking the Cybersecurity Problem
How IT Security Organizations are Attacking the Cybersecurity Problem
The COVID-19 pandemic turned the world -- and enterprise computing -- on end. Here's a look at how cybersecurity teams are retrenching their defense strategies, rebuilding their teams, and selecting new technologies to stop the oncoming rise of online attacks.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2020-9417
PUBLISHED: 2020-10-20
The Transaction Insight reporting component of TIBCO Software Inc.'s TIBCO Foresight Archive and Retrieval System, TIBCO Foresight Archive and Retrieval System Healthcare Edition, TIBCO Foresight Operational Monitor, TIBCO Foresight Operational Monitor Healthcare Edition, TIBCO Foresight Transaction...
CVE-2020-15264
PUBLISHED: 2020-10-20
The Boxstarter installer before version 2.13.0 configures C:\ProgramData\Boxstarter to be in the system-wide PATH environment variable. However, this directory is writable by normal, unprivileged users. To exploit the vulnerability, place a DLL in this directory that a privileged service is looking ...
CVE-2020-15269
PUBLISHED: 2020-10-20
In Spree before versions 3.7.11, 4.0.4, or 4.1.11, expired user tokens could be used to access Storefront API v2 endpoints. The issue is patched in versions 3.7.11, 4.0.4 and 4.1.11. A workaround without upgrading is described in the linked advisory.
CVE-2019-9080
PUBLISHED: 2020-10-20
DomainMOD before 4.14.0 uses MD5 without a salt for password storage.
CVE-2020-15931
PUBLISHED: 2020-10-20
Netwrix Account Lockout Examiner before 5.1 allows remote attackers to capture the Net-NTLMv1/v2 authentication challenge hash of the Domain Administrator (that is configured within the product in its installation state) by generating a single Kerberos Pre-Authentication Failed (ID 4771) event on a ...