Trellix Insights: Multiple threat groups exploited Microsoft Exchange vulnerabilities
Technical Articles ID:
KB95194
Last Modified: 2022-09-05 09:03:40 Etc/GMT
Last Modified: 2022-09-05 09:03:40 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
Multiple threat groups exploited the ProxyLogon Microsoft Exchange Server vulnerabilities to gain access and exfiltrate sensitive information. Some of the attacks downloaded a Cobalt Strike web shell after the chain of defects were utilized, while other attacks downloaded open-source tools to check for accounts and backdoors for persistence.
Our Threat Research team gathers and analyzes information from multiple open and closed sources before disseminating intelligence reports. This campaign was researched by AhnLab 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.
meta: description = "Detects web shells dropped by CVE-2021-27065. All actors, not specific to HAFNIUM. TLP:WHITE" author = "Joe Hannon, Microsoft Threat Intelligence Center (MSTIC)" date = "2021-03-05" reference = "https://www.microsoft.com/security/blog/2021/03/02/hafnium-targeting-exchange-servers/" strings: $script1 = "script language" ascii wide nocase $script2 = "page language" ascii wide nocase $script3 = "runat=\"server\"" ascii wide nocase $script4 = "/script" ascii wide nocase $externalurl = "externalurl" ascii wide nocase $internalurl = "internalurl" ascii wide nocase $internalauthenticationmethods = "internalauthenticationmethods" ascii wide nocase $extendedprotectiontokenchecking = "extendedprotectiontokenchecking" ascii wide nocase condition: filesize < 50KB and any of ($script*) and ($externalurl or $internalurl) and $internalauthenticationmethods and $extendedprotectiontokenchecking } |
This Knowledge Base article discusses a specific threat that's being tracked. The list of IOCs will change over time; check Trellix Insights for the latest IOCs.
Campaign IOC
| Type | Value |
Minimum Content Versions
| Content Type | Version |
Detection Summary
| 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.
Host Intrusion Prevention:
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.
Host Intrusion Prevention:
Rule ID: 6011 Generic Application Invocation Protection
Rule ID: 1148 CMD Tool Access by a Network Aware Application
Rule ID: 1020 Windows Agent Shielding - File Access
