MalwarePublished 5 Feb 2026

Technical Analysis of Marco Stealer

Source AlienVault OTX General

Description

Marco Stealer, discovered in June 2025, is an information stealer targeting browser data, cryptocurrency wallets, and sensitive files. It employs anti-analysis techniques, string encryption, and terminates security tools. The malware collects system information, exfiltrates browser data using embedded files, and extracts cryptocurrency wallet data from browser extensions. It also targets popular services and cloud storage. Marco Stealer uses AES-256 encryption for C2 communication over HTTP. Despite recent law enforcement actions against similar threats, information stealers continue to pose significant risks to corporate environments.

Impact

For European organizations, Marco Stealer presents a significant risk to confidentiality and integrity of sensitive data, particularly browser credentials, cryptocurrency wallets, and cloud-stored files. The theft of browser data can lead to account takeovers and unauthorized access to corporate resources. Cryptocurrency wallet theft can result in direct financial losses, which is especially concerning for companies and individuals involved in digital asset management or trading. The targeting of cloud storage services threatens the exposure of intellectual property and sensitive corporate documents. The malware’s anti-analysis and security tool termination capabilities increase the likelihood of prolonged undetected infections, amplifying potential damage. Given the widespread use of browsers, cloud services, and cryptocurrency in Europe, the malware could disrupt business operations, cause financial harm, and damage reputations. The encrypted C2 communication complicates detection and response efforts, potentially delaying incident containment and remediation.

Defensive guidance

European organizations should implement multi-layered defenses tailored to the specific tactics used by Marco Stealer. This includes deploying endpoint detection and response (EDR) solutions capable of detecting anti-analysis behaviors and process termination attempts targeting security tools. Monitoring for unusual browser extension activity and restricting installation of unapproved extensions can reduce exposure to wallet theft. Network defenses should include SSL/TLS inspection and anomaly detection to identify encrypted C2 traffic patterns despite AES-256 encryption. Regularly updating and hardening cloud storage access controls, including multi-factor authentication and least privilege principles, will limit data exposure. User awareness training focused on phishing and social engineering can reduce initial infection vectors. Incident response plans should incorporate indicators of compromise such as the provided file hashes and suspicious URLs to enable rapid detection and containment. Additionally, organizations should conduct regular threat hunting exercises to identify stealthy infections and maintain up-to-date threat intelligence feeds to track evolving variants.

Indicators of compromise

URLs 1

http://217.156.50.228:8181/nujbOqrNYyLXXLmOhPpY/PNcWncSY.exe'

Hashes 13

028604d6aa556de2ae4ca6b31e600677
1042affb0ca6758ca0043112cdc7eda2
33dd8a5e234d911391cc8c301dc4a606
34deb6594098545d7ffb98844f0790bf
3a3e8f6bc70748a39ffc047b3c86a665
49ab8d4c55b7f64eaba699ef0dc9054b
5eb91d1ad26c7eced894e34710aaa28e
661a5465d9a322276ebc414f39891a8b
a98fa5fba55e470750ae74186c15fa73
18be50bcf3ef9b9ea8a97008702a39e6df2c28b1

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Description

AI analysisMachine-generated, updated 5 Feb 2026, 21:14 UTC

MITRE ATT&CK techniques9 from threat tags

Technical details

Indicators of compromise

URLs 1

Hashes 13

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