MVISION Insights: A look inside the PYSA Ransomware
Technical Articles ID:
KB95680
Last Modified: 5/19/2022
Last Modified: 5/19/2022
Environment
IMPORTANT: This Knowledge Base article discusses a specific threat that is being automatically tracked by MVISION Insights technology. The content is intended for use by MVISION Insights users, but is provided for general knowledge to all customers. Contact us for more information about MVISION Insights.
Summary
Description of Campaign
Protect Your System Amigo (PYSA), aka Mespinoza has been active since the early part of 2020, targeting high value entities with exfiltration of confidential, proprietary, and internal data. Once the group has successfully breached the target and exfiltrated the targeted data, the group encrypts the infected devices and extorts the victim with threats to sell the stolen data, should the victim refuse to pay. Typically, the malware operators target unsecure RDP with brute force attacks and occasionally use phishing campaigns to deliver the early stages of an attack. The malware operators use a combination of LOLBins, commodity malware and custom scripts to deploy tools and their dependencies to gather information, exfiltrate data, and ransom their targets.
Our ATR Team gathers and analyzes information from multiple open and closed sources before disseminating intelligence reports. This campaign was researched by SentinelOne and shared publicly.
How to use this article:
This Knowledge Base article discusses a specific threat that's being tracked. The list of IOCs will change over time; check MVISION Insights for the latest IOCs.
Campaign IOC
Minimum Content Versions
Detection Summary
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:
Endpoint Security - Exploit Prevention:
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.
VirusScan Enterprise - Access Protection Rules:
Host Intrusion Prevention:
Endpoint Security - Access Protection Rules:
Protect Your System Amigo (PYSA), aka Mespinoza has been active since the early part of 2020, targeting high value entities with exfiltration of confidential, proprietary, and internal data. Once the group has successfully breached the target and exfiltrated the targeted data, the group encrypts the infected devices and extorts the victim with threats to sell the stolen data, should the victim refuse to pay. Typically, the malware operators target unsecure RDP with brute force attacks and occasionally use phishing campaigns to deliver the early stages of an attack. The malware operators use a combination of LOLBins, commodity malware and custom scripts to deploy tools and their dependencies to gather information, exfiltrate data, and ransom their targets.
Our ATR Team gathers and analyzes information from multiple open and closed sources before disseminating intelligence reports. This campaign was researched by SentinelOne 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.
| Y |
{ meta: id = "240byxdCwyzaTk3xgjzbEa" fingerprint = "7f8819e9f76b9c97e90cd5da7ea788c9bb1eb135d8e1cb8974d6f17ecf51b3c3" version = "1.0" creation_date = "2021-03-01" first_imported = "2021-12-30" last_modified = "2021-12-30" status = "RELEASED" sharing = "TLP:WHITE" source = "BARTBLAZE" author = "@bartblaze" description = "Identifies Pysa aka Mespinoza ransomware." category = "MALWARE" malware = "PYSA" malware_type = "RANSOMWARE" mitre_att = "S0583" strings: $code = { 8a 0? 41 84 c0 75 ?? 2b ce 8b 35 ?? ?? ?? ?? 8d 41 01 50 5? 6a 07 6a 00 68 ?? ?? ?? ?? ff 7? ?? ff d? 6a 05 68 ?? ?? ?? ?? 6a 07 6a 00 68 ?? ?? ?? ?? ff 7? ?? ff d? ff 7? ?? ff 15 ?? ?? ?? ?? 8b 4? ?? 33 cd 5e e8 ?? ?? ?? ?? 8b e5 5d c3 } $s1 = "n.pysa" ascii wide fullword $s2 = "%s\\Readme.README" ascii wide $s3 = "Every byte on any types of your devices was encrypted." ascii wide condition: $code or 2 of ($s*) } |
This Knowledge Base article discusses a specific threat that's being tracked. The list of IOCs will change over time; check MVISION Insights for the latest IOCs.
Minimum Content Versions
Detection Summary
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:
Rule ID: 239 Identify suspicious command parameter execution
Rule ID: 263 Detect processes accessing suspicious URLs
Rule ID: 4 Use GTI file reputation to identify trusted or malicious files
Rule ID: 263 Detect processes accessing suspicious URLs
Rule ID: 4 Use GTI file reputation to identify trusted or malicious files
Endpoint Security - Exploit Prevention:
Rule ID: 6127 Suspicious LSASS Access from PowerShell
Rule ID: 6070 Hidden PowerShell Detected
Rule ID: 6113 T1055 - Fileless Threat: Reflective Self Injection
Rule ID: 6143 T1003 - Attempt to Dump Password Hash from SAM Database
Rule ID: 6083 PowerShell Command Restriction - NonInteractive
Rule ID: 6081 PowerShell Command Restriction - NoProfile
Rule ID: 8004 Fileless Threat: Malicious PowerShell Behavior Detected
Rule ID: 6070 Hidden PowerShell Detected
Rule ID: 6113 T1055 - Fileless Threat: Reflective Self Injection
Rule ID: 6143 T1003 - Attempt to Dump Password Hash from SAM Database
Rule ID: 6083 PowerShell Command Restriction - NonInteractive
Rule ID: 6081 PowerShell Command Restriction - NoProfile
Rule ID: 8004 Fileless Threat: Malicious PowerShell Behavior Detected
Host Intrusion Prevention:
Rule ID: 6070 Hidden PowerShell Detected
Rule ID: 6113 T1055 - Fileless Threat: Reflective Self Injection
Rule ID: 6135 Unmanaged PowerShell Detected
Rule ID: 6083 PowerShell Command Restriction - NonInteractive
Rule ID: 6081 PowerShell Command Restriction - NoProfile
Rule ID: 6113 T1055 - Fileless Threat: Reflective Self Injection
Rule ID: 6135 Unmanaged PowerShell Detected
Rule ID: 6083 PowerShell Command Restriction - NonInteractive
Rule ID: 6081 PowerShell Command Restriction - NoProfile
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 programs registering as a service
Prevent creation of new executable files in the Windows folder
Prevent modification of McAfee Scan Engine files and settings
Prevent modification of McAfee files and settings
Prevent creation of new executable files in the Windows folder
Prevent modification of McAfee Scan Engine files and settings
Prevent modification of McAfee files and settings
Host Intrusion Prevention:
Rule ID: 1020 Windows Agent Shielding - File Access
Rule ID: 6010 Generic Application Hooking Protection
Rule ID: 6053 Accessing other users home directory
Rule ID: 1148 CMD Tool Access by a Network Aware Application
Rule ID: 6011 Generic Application Invocation Protection
Rule ID: 1001 Windows Agent Shielding - File Modification
Rule ID: 412 Double File Extension Execution
Rule ID: 2806 Attempt to create a hardlink to a file
Rule ID: 6010 Generic Application Hooking Protection
Rule ID: 6053 Accessing other users home directory
Rule ID: 1148 CMD Tool Access by a Network Aware Application
Rule ID: 6011 Generic Application Invocation Protection
Rule ID: 1001 Windows Agent Shielding - File Modification
Rule ID: 412 Double File Extension Execution
Rule ID: 2806 Attempt to create a hardlink to a file
Endpoint Security - Access Protection Rules:
Creating new executable files in the Windows folder
Remotely accessing local files or folders
Remotely accessing local files or folders
