Attackers also Deploy a Cryptominer and Lockbit Ransomware

OXFORD, U.K.  — avril 12, 2022 —

Sophos, a global leader in next-generation cybersecurity, today released findings on how attackers breached and spent five months inside a regional government server in the U.S., using it to browse online for a mix of hacker and IT administration tools that could help them carry out the attack. The attackers also installed a cryptominer before exfiltrating data and deploying Lockbit ransomware. The findings are detailed in a new article, “Attackers Linger on Government Agency Computers Before Deploying Lockbit Ransomware,” and suggest that multiple attackers infiltrated the vulnerable server. The attack was contained and investigated by Sophos’ incident response team.

“This was a very messy attack. Working together with the target, Sophos researchers were able to build a picture that started with what appears to be novice attackers breaking into the server, poking around the network and using the compromised server to Google a combination of pirated and free versions of hacker and legitimate admin tools to use in their attack. They then seemed unsure of what to do next,” said Andrew Brandt, principal security researcher at Sophos. “About four months after the initial breach, the nature of the attack activity changed, in some cases so drastically that it suggests attackers with very different skills had joined the fray. These attackers went on to attempt to uninstall security software. They eventually stole data and encrypted files on several machines by deploying Lockbit ransomware.”

The Sequence of Attack

Sophos researchers found that the initial point of access for the attack was an open remote desktop protocol (RDP) port on a firewall that was configured to provide public access to a server. The attackers breached the server in September 2021. They then used a browser on the breached server to search online for the tools to use for hacking and attempted to install them. In some cases, the search for tools led the attackers to shady download sites that delivered adware to the hacked server, instead of the tools they were looking for.

The research shows that attackers’ behaviors changed significantly in mid-January, with signs of more skilled and focused activity. These attackers attempted to remove the malicious cryptominer and uninstall security software, taking advantage of the fact that the target had inadvertently left a protective feature disabled after completing maintenance. The attackers then collected and exfiltrated data and deployed the Lockbit ransomware. The ransomware attack had limited success and the attackers failed to encrypt data on some machines.

Staying Protected

The tools the attackers tried to install for malicious purposes included Advanced Port Scanner, FileZilla, LaZagne, mimikatz, NLBrute, Process Hacker, PuTTY, Remote Desktop Passview, RDP Brute Forcer, SniffPass, and WinSCP. The attackers also installed commercial remote access tools, including ScreenConnect and AnyDesk.

“If a member of the IT team hasn’t downloaded them for a specific purpose, the presence of such tools on machines on your network is a red flag for an ongoing or imminent attack,” said Brandt. “Unexpected or unusual network activity, such as a machine scanning the network is another such indicator. Repeated RDP login failures on a machine only accessible inside the network is a sign someone might be using a brute-force tool to try to move laterally. As are active connections from commercial remote access tools the IT team has not installed or may have used in the past but have not used for a while.

“A robust, proactive, 24/7 defense-in-depth approach will help to prevent such an attack from taking hold and unfolding. The most important first step is to try to prevent attackers from gaining access to a network in the first place, for example by implementing multi-factor authentication and setting firewall rules to block remote access to RDP ports in the absence of a VPN connection.”

For further information read the article, “Attackers Linger on Government Agency Computers Before Deploying Lockbit Ransomware” on Sophos News.

À propos de Sophos

Sophos est un leader mondial de la cybersécurité qui protège 600000organisations à travers le monde grâce à une plateforme optimisée par l’IA et à des services fournis par des experts. Sophos accompagne les entreprises, quel que soit leur niveau de maturité en matière de cybersécurité, et évolue avec elles pour déjouer les cyberattaques. Ses solutions offrent une combinaison optimale entre apprentissage automatique, automatisation et renseignements sur les menaces en temps réel, à laquelle s’ajoute l’expertise humaine de l’équipe Sophos X-Ops, qui travaille en première ligne pour assurer la surveillance, la détection et la réponse aux menaces 24h/24 et 7j/7.
Sophos propose des services managés de détection et de réponse (MDR) de pointe, ainsi qu’un portefeuille complet de technologies de cybersécurité, parmi lesquelles des solutions de sécurité Endpoint, réseau, email et cloud, ainsi que des solutions de détection et de réponse étendues (XDR), de détection et de réponse aux menaces liées à l’identité (ITDR) et de SIEM de nouvelle génération. Associées à des services de conseil spécialisés, ces capacités aident les entreprises à réduire leurs risques de manière proactive et à répondre plus rapidement, tout en bénéficiant de la visibilité et de l’évolutivité nécessaires pour garder une longueur d’avance sur les menaces en constante évolution.
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