hunting-for-data-exfiltration-indicators

Hunt for data exfiltration through network traffic analysis, detecting unusual data flows, DNS tunneling, cloud storage uploads, and encrypted channel abuse.

4,032 stars

Best use case

hunting-for-data-exfiltration-indicators is best used when you need a repeatable AI agent workflow instead of a one-off prompt.

Hunt for data exfiltration through network traffic analysis, detecting unusual data flows, DNS tunneling, cloud storage uploads, and encrypted channel abuse.

Teams using hunting-for-data-exfiltration-indicators should expect a more consistent output, faster repeated execution, less prompt rewriting.

When to use this skill

  • You want a reusable workflow that can be run more than once with consistent structure.

When not to use this skill

  • You only need a quick one-off answer and do not need a reusable workflow.
  • You cannot install or maintain the underlying files, dependencies, or repository context.

Installation

Claude Code / Cursor / Codex

$curl -o ~/.claude/skills/hunting-for-data-exfiltration-indicators/SKILL.md --create-dirs "https://raw.githubusercontent.com/mukul975/Anthropic-Cybersecurity-Skills/main/skills/hunting-for-data-exfiltration-indicators/SKILL.md"

Manual Installation

  1. Download SKILL.md from GitHub
  2. Place it in .claude/skills/hunting-for-data-exfiltration-indicators/SKILL.md inside your project
  3. Restart your AI agent — it will auto-discover the skill

How hunting-for-data-exfiltration-indicators Compares

Feature / Agenthunting-for-data-exfiltration-indicatorsStandard Approach
Platform SupportNot specifiedLimited / Varies
Context Awareness High Baseline
Installation ComplexityUnknownN/A

Frequently Asked Questions

What does this skill do?

Hunt for data exfiltration through network traffic analysis, detecting unusual data flows, DNS tunneling, cloud storage uploads, and encrypted channel abuse.

Where can I find the source code?

You can find the source code on GitHub using the link provided at the top of the page.

Related Guides

SKILL.md Source

# Hunting for Data Exfiltration Indicators

## When to Use

- When hunting for data theft in compromised environments
- After detecting unusual outbound data volumes or patterns
- When investigating potential insider threat data theft
- During incident response to determine what data was stolen
- When threat intel indicates data exfiltration campaigns targeting your sector

## Prerequisites

- Network proxy/firewall logs with byte-level data transfer metrics
- DLP solution or CASB with cloud upload visibility
- DNS query logs for DNS exfiltration detection
- Email gateway logs for attachment monitoring
- SIEM with data volume anomaly detection capabilities

## Workflow

1. **Define Exfiltration Channels**: Identify potential channels (HTTP/S uploads, DNS tunneling, email attachments, cloud storage, removable media, encrypted protocols).
2. **Baseline Normal Data Flows**: Establish baseline outbound data transfer volumes per user, host, and destination over a 30-day window.
3. **Detect Volume Anomalies**: Identify hosts or users transferring significantly more data than baseline to external destinations.
4. **Analyze Transfer Destinations**: Check destination domains/IPs against threat intel, identify newly registered domains, personal cloud storage, and foreign infrastructure.
5. **Inspect Protocol Abuse**: Look for DNS tunneling (large/frequent TXT queries), ICMP tunneling, or data hidden in allowed protocols.
6. **Correlate with File Access**: Link exfiltration indicators to file access events on sensitive file shares, databases, or repositories.
7. **Report and Contain**: Document findings with evidence, estimate data exposure, and recommend containment actions.

## Key Concepts

| Concept | Description |
|---------|-------------|
| T1041 | Exfiltration Over C2 Channel |
| T1048 | Exfiltration Over Alternative Protocol |
| T1048.001 | Exfiltration Over Symmetric Encrypted Non-C2 |
| T1048.002 | Exfiltration Over Asymmetric Encrypted Non-C2 |
| T1048.003 | Exfiltration Over Unencrypted/Obfuscated Non-C2 |
| T1567 | Exfiltration Over Web Service |
| T1567.002 | Exfiltration to Cloud Storage |
| T1052 | Exfiltration Over Physical Medium |
| T1029 | Scheduled Transfer |
| T1030 | Data Transfer Size Limits (staging) |
| T1537 | Transfer Data to Cloud Account |
| T1020 | Automated Exfiltration |

## Tools & Systems

| Tool | Purpose |
|------|---------|
| Splunk | SIEM for data volume analysis and SPL queries |
| Zeek | Network metadata for data flow analysis |
| Microsoft Defender for Cloud Apps | CASB for cloud exfiltration |
| Netskope | Cloud DLP and exfiltration detection |
| Suricata | Network IDS for protocol anomaly detection |
| RITA | DNS exfiltration and beacon detection |
| ExtraHop | Network traffic analysis for data flow |

## Common Scenarios

1. **Cloud Storage Exfiltration**: User uploads sensitive documents to personal Google Drive or Dropbox via browser.
2. **DNS Tunneling**: Malware exfiltrates data encoded in DNS subdomain queries to attacker-controlled nameserver.
3. **HTTPS Upload**: Compromised system POSTs large data blobs to C2 server over encrypted HTTPS.
4. **Email Attachment Exfiltration**: Insider forwards sensitive documents to personal email accounts.
5. **Staging and Compression**: Adversary stages data in compressed archives before slow exfiltration to avoid detection.

## Output Format

```
Hunt ID: TH-EXFIL-[DATE]-[SEQ]
Exfiltration Channel: [HTTP/DNS/Email/Cloud/USB]
Source: [Host/User]
Destination: [Domain/IP/Service]
Data Volume: [Bytes/MB/GB]
Time Period: [Start - End]
Protocol: [HTTPS/DNS/SMTP/SMB]
Files Involved: [Count/Types]
Risk Level: [Critical/High/Medium/Low]
Confidence: [High/Medium/Low]
```

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