A threat actor exploited a vulnerability in Langflow to access an organization’s instance and abuse it in an agentic ransomware attack, cloud security firm Sysdig reports.
Langflow is a Python-based, LLM-agnostic open source framework used for building LLM-driven applications and agent workflows.
As part of the attack, a threat actor tracked as JadePuffer gained access to an internet-exposed Langflow instance through the exploitation of CVE-2025-3248 (CVSS score of 9.8), a critical missing authentication vulnerability disclosed in April.
Successful exploitation of the bug allows attackers to execute arbitrary Python code on the host on which Langflow is running. CISA flagged the flaw as exploited in early May.
After gaining code execution, JadePuffer used the LLM for reconnaissance and swept the system for secrets, including API keys, cloud credentials, cryptocurrency wallets, configuration files, and database credentials.
Next, the threat actor dumped Langflow’s Postgres database to harvest the secrets in it, scanned the reachable internal address space and named services, probed for MinIO addresses for further credential extraction, and deployed a cron job for persistent access to the Langflow server.
Throughout this initial phase, the LLM was observed adapting its actions in real time to complete tasks, extract credentials from different file types, and log into discovered endpoints.
During the second phase of the attack, JadePuffer used the LLM to pivot to a production server hosting a MySQL database and an Alibaba Naming and Configuration Service (Nacos) configuration platform.
Widely used in Alibaba microservice architectures, Nacos has been plagued by various security bypasses and uses a well-known default JWT signing key that allows for easy token forgery.
Lateral movement and encryption
JadePuffer connected to this server using a payload that contained root credentials for the MySQL port and abused the LLM to target the Nacos service through multiple vectors.
“That includes exploiting the auth-bypass family (CVE-2021-29441), forging a valid JWT using Nacos’s well-known default signing key, and, with root database access, injecting a backdoor administrator directly into the Nacos backing database,” Sysdig explains.
During the attack, the LLM adjusted the payload to pass login verification, checked for User Defined Functions (UDF), which can lead to OS command execution, and issued a completion marker before ransomware deployment.
Next, it encrypted 1,342 Nacos service configuration items and created an extortion table containing the ransom demand, a payment address, and a contact email address. The encryption key was randomly generated but never persisted or transmitted, essentially preventing data recovery.
“Captured payloads show the LLM escalating from row-level deletion to dropping entire database schemas, narrating its own targeting rationale,” Sysdig notes.
The payloads analyzed by the cybersecurity firm contained natural-language commentary on each action, indicative of LLM-generated code. Furthermore, they showed how the LLM corrected its actions to address failures and provide accurate diagnoses.
“During the operation, the LLM parsed free-text context presented by the target and took an action that only makes sense if that text was read and understood, rather than pattern-matched by a scanner. This behavior recurred across sessions weeks apart,” Sysdig notes.
According to the company, this attack shows that LLM agents significantly lower the barrier for malicious operations, which now require a capable model rather than a capable human. The AI combined known techniques in a successful attack against neglected infrastructure, with close to zero cost to the attacker.
“Defenders should expect the volume and breadth of such campaigns to rise as agentic tooling matures, and they should treat exposed application servers, unhardened configuration stores, and internet-facing database admin accounts as the first surfaces that will be attacked,” Sysdig notes.
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