Trellix Insights: 2021 Buer Loader Campaigns
Technical Articles ID:
KB95173
Last Modified: 2022-09-06 05:13:20 Etc/GMT
Last Modified: 2022-09-06 05:13:20 Etc/GMT
Environment
IMPORTANT: This Knowledge Base article discusses a specific threat that is being automatically tracked by Trellix Insights technology. The content is intended for use by Trellix Insights users, but is provided for general knowledge to all customers. Contact us for more information about Trellix Insights.
Summary
Buer Loader was discovered in underground forums in 2019 and continues to be updated throughout 2021. Recent campaigns use either DHL shipping or Covid-19 lures to convince victims to open the malicious attachment. Updated variants are written in the Rust programming language and use signed XLL files to deliver the malicious software. Buer Loader is used to deliver various payloads including web shells and ransomware.
Our Threat Research team gathers and analyzes information from multiple open and closed sources before disseminating intelligence reports. This campaign was researched by Trend Micro and shared publicly.
How to use this article:
- If a Threat Hunting table has been created, use the rules contained to search for malware related to this campaign.
- Review the product detection table and confirm that your environment is at least on the specified content version.
To download the latest content versions, go to the Security Updates page. - Scroll down and review the "Product Countermeasures" section of this article. Consider implementing them if they are not already in place.
- Review
KB91836 - Countermeasures for entry vector threats . - Review KB87843 - Dynamic Application Containment rules and best practices.
- Review KB82925 - Identify what rule corresponds to an Adaptive Threat Protection and Threat Intelligence Exchange event.
Campaign IOC
Type | Value |
Minimum Content Versions
Content Type | Version |
Detection Summary
IOC | Scanner | Detection |
IOC | Scanner | Detection |
IOC | Scanner | Detection |
IOC | Scanner | Detection |
IOC | Scanner | Detection |
Minimum set of Manual Rules to improve protection to block this campaign:
IMPORTANT: Always follow best practices when you enable new rules and signatures.
When you implement new rules or signatures, always set them to Report mode first and check the alerts generated. Resolve any issues that arise and then set the rules to Block. This step mitigates against triggering false positives and allows you to refine your configuration.
For more information, see KB87843 - List of and best practices for Endpoint Security Dynamic Application Containment rules.
Endpoint Security - Advanced Threat Protection:
Aggressive set of Manual Rules to improve protection to block this campaign:
IMPORTANT: Always follow best practices when you enable new rules and signatures.
When you implement new rules or signatures, always set them to Report mode first and check the alerts generated. Resolve any issues that arise and then set the rules to Block. This step mitigates against triggering false positives and allows you to refine your configuration.
For more information, see KB87843 - List of and best practices for Endpoint Security Dynamic Application Containment rules.
VirusScan Enterprise - Access Protection Rules:
Prevent creation of new executable files in the Windows folder
Host Intrusion Prevention:
Rule ID: 1020 Windows Agent Shielding - File Access
Rule ID: 6010 Generic Application Hooking Protection
Rule ID: 1148 CMD Tool Access by a Network Aware Application
Rule ID: 6011 Generic Application Invocation Protection
Rule ID: 2806 Attempt to create a hardlink to a file