Full Report
In threat detection, time is everything. Especially when identifying tools like NimScan—a known Potentially Unwanted Application (PUA) often associated with reconnaissance or malicious scanning activities. Microsoft Sentinel provides detection rules for such threats using Kusto Query Language (KQL), but understanding their full scope at a glance can be time-consuming. That’s where Uncoder AI’s Full Summary […] The post Uncovering PUA: NimScan Activity with Full Summary in Uncoder AI appeared first on SOC Prime.
Analysis Summary
# Tool/Technique: NimScan Activity (PUA)
## Overview
This summary details the detection logic and significance of identifying activity related to **NimScan**, which is being flagged as Potentially Unwanted Application (PUA) activity. The detection focuses primarily on process execution monitoring and file hash correlation.
## Technical Details
- Type: Malware/Tool Activity (Context suggests activity associated with a PUA or potentially malicious tool)
- Platform: Windows (Inferred from Sysmon and KQL context)
- Capabilities: Execution tracking, identifiable via file name or unique hash signature (IMPHASH).
- First Seen: April 30, 2025 (Date of article publication/analysis)
## MITRE ATT&CK Mapping
The activity described primarily relates to execution and detection evasion:
- **TA0002 - Execution**
- T1059.003 - Command and Scripting Interpreter: Windows Command Shell (Implied use of executed files)
- **TA0005 - Defense Evasion**
- T1036 - Masquerading (Relevant due to the capability of attackers renaming binaries)
## Functionality
### Core Capabilities
- **Process Creation Detection:** Monitoring for new processes named exactly `NimScan.exe`.
- **Hash-based Detection:** Utilizing IMPHASH values to identify the binary even if its external name is changed (renaming/masquerading).
### Advanced Features
- **IMPHASH Correlation:** Leveraging file structure-based hashing (IMPHASH) which persists even when attackers rename the binary, providing robust detection against masquerading attempts.
## Indicators of Compromise
- File Hashes: [Specific known hashes are implied but not explicitly listed in the provided context]
- File Names: `NimScan.exe`
- Registry Keys: [Not specified]
- Network Indicators: [Not specified]
- Behavioral Indicators: Creation of a new process named `NimScan.exe`; detection relies on matching specific IMPHASH values associated with the binary instances.
## Associated Threat Actors
- [Not explicitly mentioned in the provided text, but associated with "red team toolkits" or early-stage malware delivery, suggesting general threat actor use.]
## Detection Methods
- **Signature-based detection:** Using known file hashes (IMPHASH).
- **Behavioral detection:** Monitoring for the specific process name (`NimScan.exe` creation).
- **Specific Query Language:** Microsoft Sentinel KQL query designed to filter Sysmon Events.
## Mitigation Strategies
- Ensure Sysmon logging is active to capture process creation events.
- Utilize threat intelligence feeds that include known IMPHASH values for PUA/malware detection.
- Implement robust file integrity monitoring or application control solutions.
## Related Tools/Techniques
- Binary Renaming/Masquerading Techniques (T1036).
- Tools commonly found in Red Team toolkits.