Microsoft update on brute force and password spraying activity

The NCSC has issued advice to organisations following an update from Microsoft on malicious cyber campaigns.
Microsoft has revealed that it had identified new activity from an Advanced Persistent Threat (APT) known as NOBELIUM targeting organisations globally.
The Microsoft Threat Intelligence Center says that this activity was mostly unsuccessful.
The NCSC has observed an increase in activity as part of malicious email and password spraying campaigns against a limited number of UK organisations. We are supporting those affected and would urge all organisations to familiarise themselves with our guidance on mitigating phishing attacks, including how to block phishing emails and how to implement two-factor/multi-factor authentication:
- Phishing attacks: defending your organisation
- Multi-factor authentication for online services
- Identity and access management (part of the 10 steps to cyber security collection)
- Home working: preparing your organisation and staff
The following blog posts from Microsoft provide further details, including IoCs, detection and mitigation advice:
- New Nobelium activity – Microsoft Security Response Center
- Investigating and Mitigating Malicious Drivers – Microsoft Security Response Center
- Nobelium Resource Center – updated March 4, 2021 – Microsoft Security Response Center

Security updates released for Microsoft Exchange Servers

The National Cyber Security Centre (NCSC) is encouraging organisations to install critical updates following a number of vulnerabilities being addressed in Microsoft Exchange.
As part of Microsoft's scheduled April update cycle, a number of critical severity vulnerabilities were addressed in Microsoft Exchange. We have no information to suggest that these vulnerabilities are being used in active exploitation. However, given the recent focus on Exchange, we recommend the installation of updates as soon as practicable, as attackers may seek to build exploit capability which could be used against systems before the updates are applied.
The vulnerabilities affect Microsoft Exchange Server. The affected versions are:
- Exchange Server 2013
- Exchange Server 2016
- Exchange Server 2019
Organisations running an out-of-support version of Microsoft Exchange should update to a supported version without delay.
Exchange Online customers are already protected.
The NCSC recommends following vendor best practice advice in the mitigation of vulnerabilities. In this case, the most important aspect is to install the latest security updates immediately. The April 2021 security update fixes a number of security vulnerabilities and more information can be found on Microsoft's website.

ENISA provide statement on Microsoft Exchange vulnerabilities

The EU Agency for Cybersecurity (ENISA) has provided a statement with an assessment and advice on Microsoft Exchange vulnerabilities.
Microsoft released security updates for Microsoft (MS) Exchange server suite. Active exploitation has been observed on-premises running MS Exchange installations.
MS Exchange vulnerabilities once exploited may lead to network compromise, data exfiltration and ransomware attacks. Across the EU, an increasing number of MS Exchange installations have also been found to be the target of malicious attacks.
ENISA published a situation report which provides an assessment as well as advice and mitigation measures. It reports that threat has been assessed as severe and considers these types of attacks probable and of high risk.
The Agency calls on organisations using affected Microsoft Exchange versions to patch the flaws immediately and thoroughly investigate for potential signs of compromise.
At EU level, the EU CSIRTs Network and EU Cyber Crises Liaison Organisation Network (CyCLONe) are monitoring the situation and collecting information at both the technical and operational levels.
Microsoft is updating advisories and guidance while additional technical information and advice are provided by CERT-EU technical advisory.