Full Report
Linux Syscall Threat Detection in Splunk with Uncoder AI How It Works The detection logic here is built around monitoring use of the mknod syscall, which is rarely used in legitimate workflows but can be exploited by attackers to: Create fake block or character devices Interact with kernel interfaces Bypass file system controls or establish […] The post Linux Syscall Threat Detection in Splunk with Uncoder AI appeared first on SOC Prime.
Analysis Summary
# Tool/Technique: Linux Syscall Threat Detection (via Uncoder AI and Sigma Rules)
## Overview
This article discusses leveraging **Uncoder AI** to translate open-source threat content, specifically **Sigma rules** targeting **Linux syscalls** (via `auditd` logs), into a format readily deployable within a **Splunk SIEM** environment for real-time threat detection. The focus is on enhancing visibility into low-frequency, high-risk Linux attacker behaviors.
## Technical Details
- Type: Tool/Framework/Rule Translation Utility
- Platform: Linux (monitoring) translated for Splunk (SIEM)
- Capabilities: Conversion of Sigma rules to Splunk query language, mapping Linux field names to Splunk conventions, preserving detection semantics.
- First Seen: Not explicitly stated, but context suggests recent development alongside Uncoder AI capabilities.
## MITRE ATT&CK Mapping
*The article explicitly mentions detecting persistence techniques and covert channel creation via syscalls, which maps broadly to:*
- **TA0003 - Persistence**
- T1548 - Abuse Elevation Control Mechanism (Potentially via syscall misuse)
- **TA0011 - Command and Control**
- T1071 - Application Layer Protocol (If syscalls are used for covert communication)
*Specific syscall monitoring like `mknod` often relates to:*
- **TA0003 - Persistence**
- T1543 - Create or Modify System Process (Depending on what `mknod` is used for, e.g., creating device files for persistence)
## Functionality
### Core Capabilities
- Instant deployment of threat content (like Sigma rules) into Splunk SIEM.
- Improved coverage for Linux telemetry, specifically targeting `SYSCALL` type logs derived from `auditd`.
- Automated mapping of field names and values from the source Sigma language into Splunk-compliant schemas.
### Advanced Features
- Preservation of the original detection semantics during translation.
- Ability to implement sophisticated, high-risk behavior monitoring, such as tracking the `mknod` syscall.
- Bridging open threat intelligence standards (like Sigma) with proprietary platforms (Splunk).
## Indicators of Compromise
This section focuses on the *detection logic* rather than specific IoCs found in malware:
- File Hashes: N/A (Tool focus)
- File Names: N/A (Tool focus)
- Registry Keys: N/A (Linux focus)
- Network Indicators: N/A (Tool focus)
- Behavioral Indicators: Monitoring for specific Linux system calls, such as:
- Syscall monitoring via `auditd` entries typed as `SYSCALL`.
- Specific monitoring for the `mknod` syscall.
## Associated Threat Actors
- No specific threat actors are named in connection with this detection method, but it is aimed at general Linux-based APT activity that utilizes low-level system interactions.
## Detection Methods
- **Translated Signatures:** Deployed as Splunk queries generated from Sigma rules using Uncoder AI.
- **Telemetry Focus:** Utilizing `auditd` logs, specifically filtering for `SYSCALL` events.
- **Specific Rule Target:** Monitoring for techniques like persistence creation or covert channel activity at the syscall level.
## Mitigation Strategies
- **Telemetry Configuration:** Ensuring robust configuration of the Linux `auditd` service to capture necessary syscall events.
- **Tool Implementation:** Adopting Uncoder AI/Detection as Code platforms to rapidly translate and deploy high-fidelity threat content.
- **Focus Area:** Hardening defenses specifically around low-level system functions that attackers might abuse for persistence or system modification.
## Related Tools/Techniques
- **Uncoder AI:** The primary tool used to facilitate the translation.
- **Sigma:** The open-source rule format being translated.
- **Splunk:** The target SIEM platform for the final detection rules.
- **auditd:** The fundamental Linux logging mechanism providing the raw syscall data.