US Cert Alert – Alert (AA23-025A) Protecting Against Malicious Use of Remote Monitoring and Management Software

Using portable executables of RMM software provides a way for actors to establish local user access without the need for administrative privilege and full software installation-effectively bypassing common software controls and risk management assumptions.

In October 2022, CISA used trusted third-party reporting, to conduct retrospective analysis of EINSTEIN-a federal civilian executive branch (FCEB)-wide intrusion detection system (IDS) operated and monitored by CISA-and identified suspected malicious activity on two FCEB networks:

In mid-June 2022, malicious actors sent a phishing email containing a phone number to an FCEB employee’s government email address.
The employee called the number, which led them to visit the malicious domain, myhelpcare[.]online.
In mid-September 2022, there was bi-directional traffic between an FCEB network and myhelpcare[.]cc.
Based on further EINSTEIN analysis and incident response support, CISA identified related activity on many other FCEB networks.
The authoring organizations assess this activity is part of a widespread, financially motivated phishing campaign and is related to malicious typosquatting activity reported by Silent Push in the blog post Silent Push uncovers a large trojan operation featuring Amazon, Microsoft, Geek Squad, McAfee, Norton, and Paypal domains.

Malicious Cyber Activity
The authoring organizations assess that since at least June 2022, cyber criminal actors have sent help desk-themed phishing emails to FCEB federal staff’s personal, and government email addresses.
The emails either contain a link to a “first-stage” malicious domain or prompt the recipients to call the cybercriminals, who then try to convince the recipients to visit the first-stage malicious domain.
See figure 1 for an example phishing email obtained from an FCEB network.

The recipient visiting the first-stage malicious domain triggers the download of an executable.
The executable then connects to a “second-stage” malicious domain, from which it downloads additional RMM software.

CISA noted that the actors did not install downloaded RMM clients on the compromised host.
Instead, the actors downloaded AnyDesk and ScreenConnect as self-contained, portable executables configured to connect to the actor’s RMM server.

Note: Portable executables launch within the user’s context without installation.
Because portable executables do not require administrator privileges, they can allow execution of unapproved software even if a risk management control may be in place to audit or block the same software’s installation on the network.
Threat actors can leverage a portable executable with local user rights to attack other vulnerable machines within the local intranet or establish long term persistent access as a local user service.

CISA has observed that multiple first-stage domain names follow naming patterns used for IT help/support themed social-engineering, e.g., hservice[.]live, gscare[.]live, nhelpcare[.]info, deskcareme[.]live, nhelpcare[.]cc).
According to Silent Push, some of these malicious domains impersonate known brands such as, Norton, GeekSupport, Geek Squad, Amazon, Microsoft, McAfee, and PayPal.
CISA has also observed that the first-stage malicious domain linked in the initial phishing email periodically redirects to other sites for additional redirects and downloads of RMM software.

Use of Remote Monitoring and Management Tools
In this campaign, after downloading the RMM software, the actors used the software to initiate a refund scam.
They first connected to the recipient’s system and enticed the recipient to log into their bank account while remaining connected to the system.
The actors then used their access through the RMM software to modify the recipient’s bank account summary.
The falsely modified bank account summary showed the recipient was mistakenly refunded an excess amount of money.
The actors then instructed the recipient to “refund” this excess amount to the scam operator.
Although this specific activity appears to be financially motivated and targets individuals, the access could lead to additional malicious activity against the recipient’s organization-from both other cybercriminals and APT actors.
Network defenders should be aware that:

Although the cybercriminal actors in this campaign used ScreenConnect and AnyDesk, threat actors can maliciously leverage any legitimate RMM software.
Because threat actors can download legitimate RMM software as self-contained, portable executables, they can bypass both administrative privilege requirements and software management control policies.
The use of RMM software generally does not trigger antivirus or antimalware defenses.
Malicious cyber actors are known to leverage legitimate RMM and remote desktop software as backdoors for persistence and for C2.
RMM software allows cyber threat actors to avoid using custom malware.
Threat actors often target legitimate users of RMM software.
Targets can include managed service providers (MSPs) and IT help desks, who regularly use legitimate RMM software for technical and security end-user support, network management, endpoint monitoring, and to interact remotely with hosts for IT-support functions.
These threat actors can exploit trust relationships in MSP networks and gain access to a large number of the victim MSP’s customers.
MSP compromises can introduce significant risk-such as ransomware and cyber espionage-to the MSP’s customers.

The authoring organizations strongly encourage network defenders to apply the recommendations in the Mitigations section of this CSA to protect against malicious use of legitimate RMM software.