On 2026-05-21, ProjectDiscovery (author Prince Chaddha) published a walkthrough of its autonomous AI red-team agent, Neo, compromising a simulated AWS environment end to end in roughly 2.5 hours with no human intervention between phases. The initial target was a JetBrains TeamCity On-Premises 2023.11.2 (build 147486) server exposed on port 8111 and left unpatched against CVE-2024-27198. Neo reached superadmin access in approximately 82 seconds.

CVE-2024-27198 (CVSS 3.1 9.8, CWE-288, reported by Rapid7 on 2024-02-20 and patched by JetBrains in 2023.11.4 on 2024-03-04) is an alternative-path authentication bypass. Per Rapid7's technical disclosure, the flaw lives in the BaseController class of web-openapi.jar, specifically updateViewIfRequestHasJspParameter: a request that (1) targets a non-existent resource returning HTTP 404, (2) carries a query parameter named jsp holding an authenticated API path, and (3) appends a path-parameter segment ending in `.jsp`, is routed to the authenticated path without a session. The canonical fingerprinting request is `GET /hax?jsp=/app/rest/server;.jsp`. A companion flaw, CVE-2024-27199 (CVSS 7.3), achieves a similar effect through classic `../` path traversal under prefixes such as `/res/`, `/update/`, and `/.well-known/acme-challenge/` (e.g. `/res/../admin/diagnostic.jsp`), and can be used to overwrite the HTTPS certificate or leak diagnostic data.

In the Neo engagement, the agent used the `jsp` bypass to mint a persistent superadmin API token (`POST /hax?jsp=/app/rest/users/id:1/tokens/{tokenName};.jsp`) that survived server restarts, then read a project's build configuration parameters (`GET /app/rest/projects/id:{projectId}/parameters;.jsp`) and recovered a production database connection string with a plaintext password, a base64-encoded SSH deploy key, a JWT signing secret, and a live third-party payment API key — all stored in plaintext inside TeamCity build configuration.

Because the TeamCity host still had IMDSv1 enabled, Neo created a new build step that queried the EC2 Instance Metadata Service (link-local address 169.254.169.254) and obtained short-lived AWS STS credentials tied to an over-permissioned CI/CD IAM role (S3 read, SSM Parameter Store read, EC2 describe, RDS describe) valid for more than five hours. With those credentials it pulled a compressed SQL database backup containing roughly 1,000 customer PII records (names, emails, phone numbers, partial SSNs, partial card numbers, subscription tier, MRR) from one S3 bucket, found a legacy, un-migrated 2022 configuration file in a build-artifacts bucket containing static long-term AWS access keys plus a monitoring-platform API key and a chat-webhook URL, and enumerated multiple SSM Parameter Store entries (database password, JWT secret duplicate, payment API key, email-provider key, incident-paging key, an internal API hostname, and an RDS endpoint).

Neo then used the previously extracted JWT signing secret to forge an admin-role bearer token offline and executed an arbitrary bash build step from the CI agent to reach a private-subnet internal REST API on port 5000 that had no public IP and relied on network placement rather than authentication for protection. The forged token was accepted by an unauthenticated `/admin` endpoint, exposing an employee roster with salaries, production database connection details, and a confirmed customer count of 847,295 records. A separate `/api/v1/orders` endpoint concatenated the JWT `sub` claim directly into a SQL query (confirmed via an error message leaking the query structure) but was not exploited further because database access was already established through other means. Finally, Neo located a TeamCity internal.properties flag (`rest.debug.database.allow.query.prefixes=select`) enabling an undocumented debug SQL endpoint and used the earlier admin token to run a SELECT against the TeamCity users table, extracting bcrypt-hashed credentials for three accounts; the hashes used an outdated, weak cost factor but were not cracked during the engagement.

The findings illustrate a now-familiar real-world pattern: CVE-2024-27198 and CVE-2024-27199 were mass-exploited beginning around 2024-03-06, with signs of rogue administrative user creation observed across roughly 1,400 internet-facing TeamCity instances within days of disclosure, prompting CISA to add CVE-2024-27198 to the Known Exploited Vulnerabilities catalog on 2024-03-07. Separately reported real-world post-exploitation on compromised TeamCity servers (via this and the related CVE-2023-42793) has included rogue admin account creation, deployment of the open-source Jasmin ransomware and the BianLian ransomware group's extortion operations, XMRig cryptomining, the SparkRAT remote access tool, and Cobalt Strike beacons — none of which were part of the ProjectDiscovery lab engagement itself, but which establish the real blast radius of leaving this CVE unpatched.