Pierluigi Paganini December 06, 2018

The US Department of Homeland Security (DHS) and the FBI issued a joint alert on SamSam attacks targeting critical infrastructure.

The US Department of Homeland Security (DHS) and the FBI published a joint alert on the activity associated with the infamous SamSam ransomware.

The SamSam hackers extorted over 200 organizations, including public institutions, municipalities, and hospitals, they have caused over $30 million in losses.

In March 2018, computer systems in the City of Atlanta were infected by ransomware, the cyber attack was confirmed by the City officials.

The ransomware infection has caused the interruption of several city’s online services, including “various internal and customer-facing applications” used to pay bills or access court-related information.

One of the latest attacks hit the port of San Diego in September,  the incident impacted the processing park permits and record requests, along with other operations.

In February, SamSam ransomware infected over 2,000 computers at the Colorado Department of Transportation (DOT), the DOT has shut down the infected workstations.

In August, Sophos security firm published a report the SamSam ransomware, its experts tracked Bitcoin addresses managed by the crime gang and discovered that crooks had extorted nearly $6 million from the victims since December 2015 when it appeared in the threat landscape.

“SamSam has earned its creator(s) more than US$5.9 Million since late 2015.
74% of the known victims are based in the United States. Other regions known to have
suffered attacks include Canada, the UK, and the Middle East.” reads the report published by Sophos.

“The largest ransom paid by an individual victim, so far, is valued at US$64,000, a
significantly large amount compared to most ransomware families.”

Sophos tracked the Bitcoin addresses reported in all the SamSam versions it has spotted and discovered that 233 victims paid an overall amount of $5.9 million, the security firm also estimated that the group is netting around $300,000 per month.

A few days ago, the U.S. DoJ charged two Iranian men, Faramarz Shahi Savandi (34) and Mohammad Mehdi Shah Mansouri (27), over their alleged role in creating and spreading the infamous SamSam ransomware.

According to the joint report, most of the victims were located in the United States.

“The SamSam actors targeted multiple industries, including some within critical infrastructure. Victims were located predominately in the United States, but also internationally.” reads the alert.

“Network-wide infections against organizations are far more likely to garner large ransom payments than infections of individual systems. Organizations that provide essential functions have a critical need to resume operations quickly and are more likely to pay larger ransoms.”

SamSam actors leverage vulnerabilities in Windows servers to gain persistent access to the target network and make lateral movements to infect other hosts on the network.

According to the report, attackers used the JexBoss Exploit Kit to compromise JBoss applications. Threat actors use Remote Desktop Protocol (RDP) to gain persistent access to victims’ networks, they use brute force attacks and stolen login credentials.

After obtaining access to the victim’s network, attackers escalate privileges then they drop and execute the malware.

“After gaining access to a particular network, the SamSam actors escalate privileges for administrator rights, drop malware onto the server, and run an executable file, all without victims’ action or authorization. While many ransomware campaigns rely on a victim completing an action, such as opening an email or visiting a compromised website, RDP allows cyber actors to infect victims with minimal detection.” continues the alert.

According to the experts, attackers used stolen RDP credentials that were bought from darknet marketplaces. and used in attacks within hours of purchasing the credentials.

The alert also technical details and the following recommendations to mitigate the threat:

• Audit your network for systems that use RDP for remote communication. Disable the service if unneeded or install available patches. Users may need to work with their technology venders to confirm that patches will not affect system processes.
• Verify that all cloud-based virtual machine instances with public IPs have no open RDP ports, especially port 3389, unless there is a valid business reason to keep open RDP ports. Place any system with an open RDP port behind a firewall and require users to use a virtual private network (VPN) to access that system.
• Enable strong passwords and account lockout policies to defend against brute force attacks.
• Where possible, apply two-factor authentication.
• Regularly apply system and software updates.
• Maintain a good back-up strategy.
• Enable logging and ensure that logging mechanisms capture RDP logins. Keep logs for a minimum of 90 days and review them regularly to detect intrusion attempts.
• When creating cloud-based virtual machines, adhere to the cloud provider’s best practices for remote access.
• Ensure that third parties that require RDP access follow internal policies on remote access.
• Minimize network exposure for all control system devices. Where possible, disable RDP on critical devices.
• Regulate and limit external-to-internal RDP connections. When external access to internal resources is required, use secure methods such as VPNs. Of course, VPNs are only as secure as the connected devices.
• Restrict users’ ability (permissions) to install and run unwanted software applications.
• Scan for and remove suspicious email attachments; ensure the scanned attachment is its “true file type” (i.e., the extension matches the file header).
• Disable file and printer sharing services. If these services are required, use strong passwords or Active Directory authentication.

Pierluigi Paganini

(Security Affairs – SamSam ransomware, hacking)

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