Censys Api
Censys API v2 reference. Host reconnaissance and certificate data.
Install
$ agentstack add skill-liberty91ltd-cti-skills-censys-api ✓ scanned · ✓ verified, works with Claude Code, Cursor, and more.
Security review
✓ PassedNo issues found. Passed automated security review. · v0.1.0 How review works →
- ✓ Prompt-injection patterns
- ✓ Secret / credential exfiltration
- ✓ Dangerous shell & filesystem operations
- ✓ Untrusted network calls
- ✓ Known-malicious package signatures
What it can access
- ● Network access Used
- ✓ Filesystem access No
- ✓ Shell / process execution No
- ✓ Environment & secrets No
- ✓ Dynamic code execution No
From automated source analysis of v0.1.0. “Used” means the capability is present in the source — more access means more to trust, not that it’s unsafe.
Verified badge
Passed review? Show it. Paste this badge into your README, it links to the public security report.
Links to your public security report.[](https://agentstack.voostack.com/security/report/skill-liberty91ltd-cti-skills-censys-api) Reliability & compatibility
Declared compatibility
Compatibility is declared by the source manifest. End-to-end runtime verification is coming, see below.
We're building live execution health for every listing: tool-call success rate, median latency, uptime, and last-checked timestamps, measured, not self-reported. It isn't live yet, so we don't show numbers we can't stand behind.
How agent discovery & health will work →About
Censys API v2
Base URL
https://search.censys.io/api/v2
Authentication
Basic Auth: $CENSYS_API_ID:$CENSYS_API_SECRET
curl -s "https://search.censys.io/api/v2/hosts/{ip}" \
-u "$CENSYS_API_ID:$CENSYS_API_SECRET"Rate Limits
- Free: 250 queries/month, 5 results/query
- Paid: Higher limits based on plan
Important: Free tier is very limited. Use selectively — prioritise high-value lookups.
Key Endpoints
View Host
curl -s "https://search.censys.io/api/v2/hosts/{ip}" \
-u "$CENSYS_API_ID:$CENSYS_API_SECRET"Useful fields:
result.services[]— port, servicename, transportprotocol, bannerresult.services[].tls.certificates— TLS certificate chainresult.autonomous_system— ASN inforesult.location— geographic locationresult.operating_system— OS detectionresult.last_updated_at— scan freshness
Search Hosts
curl -s "https://search.censys.io/api/v2/hosts/search?q={query}" \
-u "$CENSYS_API_ID:$CENSYS_API_SECRET"Search syntax: services.port: 443 AND services.tls.certificates.leaf_data.subject.common_name: example.com
View Certificate
curl -s "https://search.censys.io/api/v2/certificates/{fingerprint}" \
-u "$CENSYS_API_ID:$CENSYS_API_SECRET"Common Search Queries
ip: {ip}— specific hostservices.tls.certificates.leaf_data.subject.common_name: {domain}— hosts with cert for domainservices.http.response.body_hash: {hash}— hosts serving same contentservices.jarm.fingerprint: {jarm}— hosts with same JARM fingerprint (C2 detection)labels: {label}— Censys-labeled hosts
CTI Value
Censys excels at:
- Certificate transparency analysis (finding related infrastructure)
- JARM fingerprinting (identifying C2 frameworks)
- Service banner analysis
- Historical infrastructure changes
Response Summary Format
ip:
services:
- port:
service:
banner:
certificates:
- subject_cn:
issuer:
valid_from:
valid_to:
autonomous_system:
asn:
name:
location:
country:
city:
last_updated: Source & license
This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.
- Author: Liberty91LTD
- Source: Liberty91LTD/cti-skills
- License: MIT
- Homepage: https://liberty91.com/cti-skills
Install and usage instructions live in the source repository linked above.
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Versions
- v0.1.0 Imported from the upstream source.