Detection rules › Splunk
MCP Github Suspicious Operation
This detection identifies potentially malicious activity through MCP GitHub server connections, monitoring for secret hunting in code searches, organization and repository reconnaissance, branch protection abuse, CI/CD workflow manipulation, sensitive file access, and vulnerability intelligence gathering. These patterns indicate potential supply chain attacks, credential harvesting, or pre-attack reconnaissance.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Credential Access | T1552.001 Unsecured Credentials: Credentials In Files |
Rule body splunk
name: MCP Github Suspicious Operation
id: 3348aefd-9ed8-451f-9993-1e9fa04b5530
version: 3
creation_date: '2026-02-17'
modification_date: '2026-05-13'
author: Rod Soto
status: production
type: Hunting
description: This detection identifies potentially malicious activity through MCP GitHub server connections, monitoring for secret hunting in code searches, organization and repository reconnaissance, branch protection abuse, CI/CD workflow manipulation, sensitive file access, and vulnerability intelligence gathering. These patterns indicate potential supply chain attacks, credential harvesting, or pre-attack reconnaissance.
data_source:
- MCP Server
search: |
`mcp_server` direction=inbound
| eval dest=host
| eval
query_lower=lower('params.query'),
file_path_lower=lower('params.path'),
search_query='params.query',
file_path='params.path',
target_owner='params.owner',
is_secret_hunting=if(method="search_code" AND (like(query_lower, "%password%") OR like(query_lower, "%api_key%") OR like(query_lower, "%secret%") OR like(query_lower, "%token%") OR like(query_lower, "%aws_%") OR like(query_lower, "%private_key%") OR like(query_lower, "%credential%") OR like(query_lower, "%.env%") OR like(query_lower, "%config%")), 1, 0),
is_org_recon=if(method IN ("list_repositories", "get_repository", "get_organization", "list_organization_members", "get_collaborators", "list_forks", "fork_repository"), 1, 0),
is_branch_protection_abuse=if(method IN ("update_branch_protection", "delete_branch_protection"), 1, 0),
is_workflow_manipulation=if((method IN ("create_or_update_file", "push_files")) AND like(file_path_lower, "%github/workflows%"), 1, 0),
is_sensitive_file_access=if((method IN ("create_or_update_file", "push_files", "get_file_contents")) AND (like(file_path_lower, "%dockerfile%") OR like(file_path_lower, "%package.json%") OR like(file_path_lower, "%requirements.txt%") OR like(file_path_lower, "%.env%") OR like(file_path_lower, "%settings.py%") OR like(file_path_lower, "%config%")), 1, 0),
is_issue_intel=if(method IN ("list_issues", "search_issues") AND (like(query_lower, "%vulnerability%") OR like(query_lower, "%cve%") OR like(query_lower, "%security%") OR like(query_lower, "%exploit%") OR like(query_lower, "%bug%")), 1, 0)
| where is_secret_hunting=1 OR is_org_recon=1 OR is_branch_protection_abuse=1 OR is_workflow_manipulation=1 OR is_sensitive_file_access=1 OR is_issue_intel=1
| eval attack_type=case(
is_secret_hunting=1, "Secret Hunting",
is_branch_protection_abuse=1, "Branch Protection Abuse",
is_workflow_manipulation=1, "Workflow Manipulation",
is_sensitive_file_access=1, "Sensitive File Access",
is_issue_intel=1, "Vulnerability Intelligence Gathering",
is_org_recon=1, "Organization Reconnaissance",
1=1, "Unknown")
| stats count min(_time) as firstTime max(_time) as lastTime values(method) as methods values(search_query) as search_queries values(file_path) as file_paths values(target_owner) as target_owners values(attack_type) as attack_types dc(attack_type) as attack_diversity by dest
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| table dest firstTime lastTime count attack_diversity attack_types methods search_queries file_paths target_owners
| `mcp_github_suspicious_operation_filter`
how_to_implement: Install the MCP Technology Add-on from Splunkbase and ensure MCP GitHub server logging is enabled and forwarding to the right index with proper field extraction for params.query, params.path, and params.owner. Schedule the search to run every 5-15 minutes.
known_false_positives: Legitimate developers searching code for refactoring purposes, security teams conducting authorized secret scanning, DevOps engineers modifying workflow files, and repository administrators managing branch protection settings.
references:
- https://splunkbase.splunk.com/app/8377
- https://www.docker.com/blog/mcp-horror-stories-github-prompt-injection/
- https://www.splunk.com/en_us/blog/security/securing-ai-agents-model-context-protocol.html
analytic_story:
- Suspicious MCP Activities
asset_type: Web Application
mitre_attack_id:
- T1552.001
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
category: application
security_domain: endpoint
tests:
- name: True Positive Test
attack_data:
- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/mcp/mcp.log
sourcetype: mcp:jsonrpc
source: mcp.log
test_type: unit
Stages and Predicates
Stage 1: search
`mcp_server` direction=inbound
Stage 2: eval
| eval dest=host
Stage 3: eval
| eval
query_lower=lower('params.query'),
file_path_lower=lower('params.path'),
search_query='params.query',
file_path='params.path',
target_owner='params.owner',
is_secret_hunting=if(method="search_code" AND (like(query_lower, "%password%") OR like(query_lower, "%api_key%") OR like(query_lower, "%secret%") OR like(query_lower, "%token%") OR like(query_lower, "%aws_%") OR like(query_lower, "%private_key%") OR like(query_lower, "%credential%") OR like(query_lower, "%.env%") OR like(query_lower, "%config%")), 1, 0),
is_org_recon=if(method IN ("list_repositories", "get_repository", "get_organization", "list_organization_members", "get_collaborators", "list_forks", "fork_repository"), 1, 0),
is_branch_protection_abuse=if(method IN ("update_branch_protection", "delete_branch_protection"), 1, 0),
is_workflow_manipulation=if((method IN ("create_or_update_file", "push_files")) AND like(file_path_lower, "%github/workflows%"), 1, 0),
is_sensitive_file_access=if((method IN ("create_or_update_file", "push_files", "get_file_contents")) AND (like(file_path_lower, "%dockerfile%") OR like(file_path_lower, "%package.json%") OR like(file_path_lower, "%requirements.txt%") OR like(file_path_lower, "%.env%") OR like(file_path_lower, "%settings.py%") OR like(file_path_lower, "%config%")), 1, 0),
is_issue_intel=if(method IN ("list_issues", "search_issues") AND (like(query_lower, "%vulnerability%") OR like(query_lower, "%cve%") OR like(query_lower, "%security%") OR like(query_lower, "%exploit%") OR like(query_lower, "%bug%")), 1, 0)
is_branch_protection_abuse =in(method, "update_branch_protection", "delete_branch_protection")10is_issue_intel =in(method, "list_issues", "search_issues") AND like(query_lower, "%vulnerability%") OR like(query_lower, "%cve%") OR like(query_lower, "%security%") OR like(query_lower, "%exploit%") OR like(query_lower, "%bug%")10is_org_recon =in(method, "list_repositories", "get_repository", "get_organization", "list_organization_members", "get_collaborators", "list_forks", "fork_repository")10is_secret_hunting =method = "search_code" AND like(query_lower, "%password%") OR like(query_lower, "%api_key%") OR like(query_lower, "%secret%") OR like(query_lower, "%token%") OR like(query_lower, "%aws_%") OR like(query_lower, "%private_key%") OR like(query_lower, "%credential%") OR like(query_lower, "%.env%") OR like(query_lower, "%config%")10is_sensitive_file_access =in(method, "create_or_update_file", "push_files", "get_file_contents") AND like(file_path_lower, "%dockerfile%") OR like(file_path_lower, "%package.json%") OR like(file_path_lower, "%requirements.txt%") OR like(file_path_lower, "%.env%") OR like(file_path_lower, "%settings.py%") OR like(file_path_lower, "%config%")10is_workflow_manipulation =in(method, "create_or_update_file", "push_files") AND like(file_path_lower, "%github/workflows%")10Stage 4: where
| where is_secret_hunting=1 OR is_org_recon=1 OR is_branch_protection_abuse=1 OR is_workflow_manipulation=1 OR is_sensitive_file_access=1 OR is_issue_intel=1
Stage 5: eval
| eval attack_type=case(
is_secret_hunting=1, "Secret Hunting",
is_branch_protection_abuse=1, "Branch Protection Abuse",
is_workflow_manipulation=1, "Workflow Manipulation",
is_sensitive_file_access=1, "Sensitive File Access",
is_issue_intel=1, "Vulnerability Intelligence Gathering",
is_org_recon=1, "Organization Reconnaissance",
1=1, "Unknown")
attack_type =is_secret_hunting = 1"Secret Hunting"is_branch_protection_abuse = 1"Branch Protection Abuse"is_workflow_manipulation = 1"Workflow Manipulation"is_sensitive_file_access = 1"Sensitive File Access"is_issue_intel = 1"Vulnerability Intelligence Gathering"is_org_recon = 1"Organization Reconnaissance""Unknown"Stage 6: stats
| stats count min(_time) as firstTime max(_time) as lastTime values(method) as methods values(search_query) as search_queries values(file_path) as file_paths values(target_owner) as target_owners values(attack_type) as attack_types dc(attack_type) as attack_diversity by dest
Stage 7: search
| `security_content_ctime(firstTime)`
Stage 8: search
| `security_content_ctime(lastTime)`
Stage 9: table
| table dest firstTime lastTime count attack_diversity attack_types methods search_queries file_paths target_owners
Stage 10: search
| `mcp_github_suspicious_operation_filter`
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
direction | eq |
|
is_branch_protection_abuse | eq |
|
is_issue_intel | eq |
|
is_org_recon | eq |
|
is_secret_hunting | eq |
|
is_sensitive_file_access | eq |
|
is_workflow_manipulation | eq |
|
sourcetype | eq |
|