Topline Takeaways
- Industry target: Consumer Cyclicals
- Attacker methods:
- Scheduled tasks – 15 tasks named 1-15 to execute .bat and .vbs scripts
- PowerShell scripts using -ExecutionPolicy Bypass option
- Recommended mitigations:
- Scripting language controls.
- Ensure the use of least privilege access controls.
Incident Timeline for 2024-09-25
On September 25, 2024, Blackpoint’s MDR technology alerted our Active SOC to suspicious PowerShell alerts on the host of a Consumer Cyclicals partner. Initial investigation found that the activity was tied to two different PowerShell execution; both scripts started with the -ExecutionPolicy Bypass option that allows PowerShell to bypass some of the built in restrictions.
Further analysis into the host found that the source of the activity appeared to be related to a batch script called Antivirus-Update.bat, which was located in the user’s %APPDATA%\Local. The Blackpoint Active SOC also observed 15 different scheduled tasks on the host named 1-15. The tasks were either executing a 1.bat, 2.bat, 855443.vbs, 866554.vbs, or 844332.vbs. Blackpoint’s SOC isolated the affected host and deleted the scheduled tasks.
Blackpoint’s Adversary Pursuit Group (APG) conducted additional research into the scripts and identified the following:
- tmp9EB6.tmp.ps1 is a PowerShell script that automates user-like interactions with Microsoft Edge over a period of 60 hours. It conducts idle detection, automated browsing, screen overlay, user activity monitoring, and process control.
- Antivirus-Update.bat was used to created the scheduled tasks for persistence.
- 5 is a PowerShell script that performs multiple actions over a period of 9 minutes, including capturing screenshots, collecting system information, prepares the data for transmission, sends the data to a remote server, and deletes the temporary screenshot files and repeats the process after a 15 second wait period.
More About Malicious Use of PowerShell Scripts
PowerShell is a Microsoft tool that combines a command-line shell and scripting language to automate tasks, build, test, and deploy solutions. PowerShell is cross-platform, built in Windows systems, and can be executed in memory.
PowerShell scripts are an attractive tool for threat actors due to their use, the ability to blend into “normal” activity, and the ability to use encoded PowerShell commands to obfuscate their activities. In this incident, the threat actor appeared to use PowerShell scripts in an attempt to steal information including screenshots and system information.
APG Threat Analysis for PowerShell Scripts
Blackpoint’s APG predicts the continued use of PowerShell scripts by threat actors for execution in 2024, as observed in incidents involving our partners in Industrials on August 21, 2024, and Government on April 19,2024. Additionally, Blackpoint’s APG has tracked 35 ransomware operations and 21 threat actors that have been reported to use PowerShell scripts for execution.
Mitigations
- Scripting language controls: Implement strict controls on the use of scripting languages as threat actors often rely on them for execution.
- Least Privilege Access Control: Limit user access to the necessary resources to reduce the ability to execute scripts.