Research Details the Day-by-Day Unfolding of a Human-Operated Conti Attack Using Fileless Ransomware, Background on the Ransomware’s Behaviors, and Defender Advice
OXFORD, United Kingdom, Feb. 16, 2021 (GLOBE NEWSWIRE) -- Sophos, a global leader in next-generation cybersecurity, today published a three-part series on the realities of Conti ransomware, detailing how an attack unfolded over five days, its technical features and attack behaviors, and defender advice for IT admins, security researchers and security operations professionals.
One article, “A Conti Ransomware Attack Day-by-Day,” presents a timeline of an active Conti ransomware attack, from the initial compromise to the recovery of the target’s operations. Sophos Rapid Response, a 24/7 incident response team, neutralized, contained and investigated the attack. The article also includes Indicators of Compromise (IoCs), and tactics, techniques and procedures (TTPs) to help defenders look for and prepare against future Conti attacks.
A technical article by SophosLabs researchers, “Conti Ransomware: Evasive by Nature,” shows how the attackers try to obstruct analysis of the ransomware by deploying legitimate Cobalt Strike beacons onto compromised machines and then loading code directly into memory during their attacks, leaving no artefacts for investigators to find and examine.
“This was a very fast and potentially devastating attack,” said Peter Mackenzie, manager, Sophos Rapid Response. “We discovered that the attackers managed to compromise the target’s network and gain access to domain admin credentials within 16 minutes of exploiting a vulnerable firewall. Within hours, the attackers were deploying Cobalt Strike beacons to servers that would form the backbone of the ransomware attack.
“In attacks where humans are at the controls, adversaries can adapt and react to changing situations in real time. In this case, the attackers had simultaneously gained access to two servers, so when the target detected and disabled one of these – and believed they’d stopped the attack in time – the attackers simply switched and continued their attack using the second server. Having a ‘Plan B’ is a common approach for human-led attacks and a reminder that just because some suspicious activity on the network has stopped, it doesn’t mean the attack is over.
“After exfiltrating data, the attackers deployed Cobalt Strike beacons to nearly 300 devices and launched the ransomware. The target was left with little choice but to shut down critical infrastructure and work operations. The target then contacted Sophos, and we were able to start neutralizing and containing the attack within 45 minutes. Within a day, the target was able to recover unprotected affected computers and resume operations.”
Conti is a human-operated “double extortion” ransomware that steals and threatens to expose information as well as encrypting it. The Conti News site has published data stolen from at least 180 victims to date. Sophos has created a victimology profile based on the data published on Conti News (covering around 150 organizations whose data had been published at the time of analysis).
The third article, “What to Expect When You’ve Been Hit with Conti Ransomware,” provides essential guidance for IT admins facing the impact of a Conti attack. The article covers what to do immediately and then provides a 12-point checklist to help IT admins investigate the attack. The checklist walks defenders through everything the Conti attackers could do while on the network and the primary TTPs they are likely to use. The article includes recommendations for action.
“In companies without access to a designated IT security team, it’s often IT admins who are in the direct line of fire for a ransomware attack,” said Mackenzie. “They’re the ones who come into work one morning to find everything locked and a threatening ransom note on the screen, sometimes followed by threatening emails and even phone calls. Based on our first-hand threat hunting experiences, we’ve developed an action list that will help IT admins get through the deeply challenging and stressful first few hours and days after a Conti ransomware attack, understand where they can get help, and lay the foundations for a more secure future.”
Immediate Advice for Defenders
- Shut down internet-facing remote desktop protocol (RDP) to deny cybercriminals access to networks
- If you need access to RDP, put it behind a VPN connection
- Use layered security to prevent, protect and detect cyberattacks, including endpoint detection and response (EDR) capabilities and managed response teams who watch networks 24/7
- Be aware of the five early indicators an attacker is present to stop ransomware attacks
- Have an effective incident response plan in place and update it as needed. If you don’t feel confident you have the skills or resources in place to do this, to monitor threats or to respond to emergency incidents, consider turning to external experts for help
Sophos detects components of Conti under one or more of the following definitions: HPmal/Conti-B, Mem/Conti-B, or Mem/Meter-D.
IoCs and the main TTPs for Conti ransomware and the attacks covered are posted on SophosLabs’ GitHub page.
Researchers from SophosLabs and Sophos Rapid Response contributed to the series. For additional information, please reference SophosLabs Uncut and Sophos News.
Additional resources
- The three-part series on the Realities of Conti Ransomware includes:
- A Conti Ransomware Attack Day-By-Day – Analysis of a Conti attack, including Indicators of Compromise (IoCs) and tactics, techniques and procedures (TTPs)
- Conti Ransomware: Evasive By Nature – A technical overview by SophosLabs researchers
- What to Expect When You’ve Been Hit with Conti Ransomware – An essential guide for IT admins
- Learn more about Sophos’ Rapid Response service that contains, neutralizes and investigates attacks 24/7
- The four top tips for responding to a security incident from Sophos Rapid Response and the Managed Threat Response Team
- Learn how ransomware affects IT teams in Sophos’ global survey, Cybersecurity: The Human Challenge
Contact:
Hanah Johnson, sophos@marchcomms.com
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