Cybersecurity researchers have uncovered a brand new cryptojacking marketing campaign concentrating on the Docker Engine API with the aim of co-opting the cases to hitch a malicious Docker Swarm managed by the risk actor.
This enabled the attackers to “use Docker Swarm’s orchestration options for command-and-control (C2) functions,” Datadog researchers Matt Muir and Andy Giron stated in an evaluation.
The assaults leverage Docker for preliminary entry to deploy a cryptocurrency miner on compromised containers, whereas additionally fetching and executing further payloads which are chargeable for conducting lateral motion to associated hosts working Docker, Kubernetes, or SSH.
Particularly, this entails figuring out unauthenticated and uncovered Docker API endpoints utilizing Web scanning instruments, resembling masscan and ZGrab.
On weak endpoints, the Docker API is used to spawn an Alpine container after which retrieve an initialization shell script (init.sh) from a distant server (“solscan[.]reside”) that, in flip, checks if it is working as the foundation consumer and instruments like curl and wget are put in earlier than downloading the XMRig miner.
Like different cryptojacking campaigns, it makes use of the libprocesshider rootkit to cover the malicious miner course of from the consumer when working course of enumerating instruments like high and ps.
The shell script can also be designed to fetch three different shell scripts – kube.lateral.sh, spread_docker_local.sh, and spread_ssh.sh – from the identical server for lateral motion to Docker, Kubernetes, and SSH endpoints on the community.
Spread_docker_local.sh “makes use of masscan and zgrab to scan the identical LAN ranges […] for nodes with ports 2375, 2376, 2377, 4244, and 4243 open,” the researchers stated. “These ports are related to both Docker Engine or Docker Swarm.”
“For any IPs found with the goal ports open, the malware makes an attempt to spawn a brand new container with the title alpine. This container is predicated on a picture named upspin, hosted on Docker Hub by the consumer nmlmweb3.”
The upspin picture is designed to execute the aforementioned init.sh script, thus permitting the group’s malware to propagate in a worm-like style to different Docker hosts.
What’s extra, the Docker picture tag that is used to retrieve the picture from Docker Hub is laid out in a textual content file hosted on the C2 server, thereby permitting the risk actors to simply recuperate from potential takedowns by merely altering the file contents to level to a distinct container picture.
The third shell script, spread_ssh.sh, is able to compromising SSH servers, in addition to including an SSH key and a brand new consumer named ftp that allows the risk actors to remotely connect with the hosts and preserve persistent entry.
It additionally searches for numerous credential recordsdata associated to SSH, Amazon Net Providers (AWS), Google Cloud, and Samba in hard-coded file paths inside the GitHub Codespaces surroundings (i.e., the “/house/codespace/” listing), and if discovered, uploads them to the C2 server.
Within the ultimate stage, each the Kubernetes and SSH lateral motion payloads execute one other shell script referred to as setup_mr.sh that retrieves and launches the cryptocurrency miner.
Datadog stated it additionally found three different scripts hosted on the C2 server –
- ar.sh, a variant of init.sh that modifies iptables guidelines and clears logs and cron jobs to evade detection
- TDGINIT.sh, which downloads scanning instruments and drops a malicious container on every recognized Docker host
- pdflushs.sh, which installs a persistent backdoor by appending a threat-actor-controlled SSH key to the /root/.ssh/authorized_keys file
TDGINIT.sh can also be notable for its manipulation of Docker Swarm by forcing the host to go away any present Swarm it might be a part of and add it to a brand new Swarm underneath the attacker’s management.
“This permits the risk actor to increase their management over a number of Docker cases in a coordinated style, successfully turning compromised programs right into a botnet for additional exploitation,” the researchers stated.
It is at present not clear who’s behind the assault marketing campaign, though the techniques, strategies, and procedures exhibited overlap with these of a recognized risk group generally known as TeamTNT.
“This marketing campaign demonstrates that companies resembling Docker and Kubernetes stay fruitful for risk actors conducting cryptojacking at scale,” Datadog stated.
“The marketing campaign depends on Docker API endpoints being uncovered to the Web with out authentication. The malware’s potential to propagate quickly implies that even when the probabilities of preliminary entry are comparatively slim, the rewards are excessive sufficient to maintain cloud-focused malware teams motivated sufficient to proceed conducting these assaults.”
The event comes as Elastic Safety Labs make clear a complicated Linux malware marketing campaign concentrating on weak Apache servers to ascertain persistence by way of GSocket and deploy malware households resembling Kaiji and RUDEDEVIL (aka Lucifer) that facilitate distributed denial-of-service (DDoS) and cryptocurrency mining, respectively.
“The REF6138 marketing campaign concerned cryptomining, DDoS assaults, and potential cash laundering by way of playing APIs, highlighting the attackers’ use of evolving malware and stealthy communication channels,” researchers Remco Sprooten and Ruben Groenewoud stated.
