Trustwave SpiderLabs Uncovers Ov3r_Stealer Malware Spread via Phishing and Facebook Advertising. Learn More

Trustwave SpiderLabs Uncovers Ov3r_Stealer Malware Spread via Phishing and Facebook Advertising. Learn More

Managed Detection & Response

Eliminate active threats with 24/7 threat detection, investigation, and response.

Co-Managed SOC (SIEM)

Maximize your SIEM investment, stop alert fatigue, and enhance your team with hybrid security operations support.

Advisory & Diagnostics

Advance your cybersecurity program and get expert guidance where you need it most.

Penetration Testing

Test your physical locations and IT infrastructure to shore up weaknesses before exploitation.

Database Security

Prevent unauthorized access and exceed compliance requirements.

Email Security

Stop email threats others miss and secure your organization against the #1 ransomware attack vector.

Digital Forensics & Incident Response

Prepare for the inevitable with 24/7 global breach response in-region and available on-site.

Firewall & Technology Management

Mitigate risk of a cyberattack with 24/7 incident and health monitoring and the latest threat intelligence.

Microsoft Exchange Server Attacks
Stay protected against emerging threats
Rapidly Secure New Environments
Security for rapid response situations
Securing the Cloud
Safely navigate and stay protected
Securing the IoT Landscape
Test, monitor and secure network objects
Why Trustwave
About Us
Awards and Accolades
Trustwave SpiderLabs Team
Trustwave Fusion Security Operations Platform
Trustwave Security Colony
Technology Alliance Partners
Key alliances who align and support our ecosystem of security offerings
Trustwave PartnerOne Program
Join forces with Trustwave to protect against the most advance cybersecurity threats
SpiderLabs Blog

Malspam Campaign Targets Banks Using Microsoft Publisher

It's very unusual for malware authors to utilize publishing software like Microsoft Publisher which is mainly used for fancy documents and desktop publishing tasks.

So when we saw an email sample with a .pub attachment (Microsoft Office Publisher file) and the subject "Payment Advice", our suspicions were aroused. Surely this file would not be delivering anything useful to the user.



Opening the .pub file will prompt you to Enable Macros. Earlier versions of Microsoft Publisher may display instructions to "Enable Editing" and "Enable Content" .



Manually opening the VBA Editor in Microsoft Publisher and clicking ThisDocument under Project Explorer reveals the VBScript. The macro script is triggered with the function Document_Open(). As the name implies, when the file is opened, the script will access a URL and execute a downloaded file.



The code uses control objects in the forms to hide the URL it will access. It's located in the Tag Property if we examine the properties closely.



By the time we examined the sample, the URL was not accessible anymore, but a little further research indicated this URL was used for downloading a self-extracting archive, which contained the FlawedAmmyy RAT, a backdoor tool that attackers use to control your machine unknowingly. A quick analysis in our Cuckoo system confirmed that the backdoor accessed a certain IP related to FlawedAmmyy.



Machine information like "id", "os", "names" and credentials is then sent to the attacker:



As mentioned above, this campaign was unusual in the use of .pub files. It also appeared to originate from the Necurs botnet, a notorious botnet responsible for much mass malware distribution in the past. Unlike previous mass campaigns, this campaign was small and, interestingly, all of the To: addresses we saw targeted were domains belonging to banks, indicating a desire for the attackers to get a foothold within banks with the FlawedAmmyy RAT.

Indicators of Compromise(IOCs)

PUB File:

MD5 5fdeaa5e62fabc9933352efe016f1565
SHA1 7141932617f4718521bda0a960a036114769872d


File from URL(hxxp://

MD5 be6a53fbee5529a1cdbdd4345c191dfa
SHA1 985b44e7280b0293d08982c466d95ed86452fb73


Unpacked file (FlawwedAmmy RAT)

MD5 bacd1120ad0918b81d98de9b9acb69ce
SHA1 b65c2fc63ff2db8ed69ec7e856702f85f5af319e

Latest SpiderLabs Blogs

Welcome to Adventures in Cybersecurity: The Defender Series

I’m happy to say I’m done chasing Microsoft certifications (AZ104/AZ500/SC100), and as a result, I’ve had the time to put some effort into a blog series that hopefully will entertain and inform you...

Read More

Trustwave SpiderLabs: Insights and Solutions to Defend Educational Institutions Against Cyber Threats

Security teams responsible for defending educational institutions at higher education and primary school levels often find themselves facing harsh lessons from threat actors who exploit the numerous...

Read More

Breakdown of Tycoon Phishing-as-a-Service System

Just weeks after Trustwave SpiderLabs reported on the Greatness phishing-as-a-service (PaaS) framework, SpiderLabs’ Email Security team is tracking another PaaS called Tycoon Group.

Read More