Pierluigi Paganini February 16, 2024

U.S. CISA revealed that threat actors breached an unnamed state government organization via an administrator account belonging to a former employee.

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) revealed that a threat actor gained access to an unnamed state government organization’s network environment via an administrator account belonging to a former employee.

CISA and the Multi-State Information Sharing & Analysis Center (MS-ISAC) published a joint Cybersecurity Advisory (CSA) to provide network defenders with the tactics, techniques, and procedures (TTPs) utilized by a threat actor.

The government experts conducted an incident response assessment of the state government organization after its documents were posted on the dark web. The threat actor compromised network administrator credentials through the account of a former employee that was used to successfully authenticate to an internal virtual private network (VPN) access point. Then the attackers made lateral movement and executed various lightweight directory access protocol (LDAP) queries against a domain controller. The government organization also hosts its sensitive data on an Azure environment which was not accessed by the attackers.

“The logs revealed the threat actor first connected from an unknown virtual machine (VM) to the victim’s on-premises environment via internet protocol (IP) addresses within their internal VPN range. CISA and MS-ISAC assessed that the threat actor connected to the VM through the victim’s VPN with the intent to blend in with legitimate traffic to evade detection.” reads the report published by CISA.

The threat actor likely obtained the employee’s account credentials from a third-party data breach.

The threat actor likely obtained the account credentials of a second user from the virtualized SharePoint server managed by the first user. Neither of the two administrative accounts had multifactor authentication (MFA) enabled.

CISA pointed out that the victim confirmed that the administrator credentials for the second user were stored locally on this server.

Access to the virtualized SharePoint server enabled threat actors to also acquire a separate set of credentials stored on the server, granting administrative privileges to both the on-premises network and Azure Active Directory.

The report includes a lot of interesting details about the threat actor’s activity along with mitigations in accordance with the Cross-Sector Cybersecurity Performance Goals (CPGs) established by CISA and the National Institute of Standards and Technology (NIST), which are recommended to all critical infrastructure entities and network defenders.

CISA did not attribute the attack to a specific threat actor.

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Pierluigi Paganini

(SecurityAffairs – hacking, CISA)