Hello Ransomware
Ransomware delivered by exploiting a two year-old vulnerability in Microsoft SharePoint servers.
Summary
Ransomware delivered by exploiting a two year-old vulnerability in Microsoft SharePoint servers.
Affected platforms
The following platforms are known to be affected:
Microsoft SharePoint Server Versions: all prior to April 2019
Threat details
Introduction
Hello, also known as WickrMe, is ransomware that targets Microsoft SharePoint servers.
Delivery
The ransomware is delivered by exploiting a vulnerability in Microsoft SharePoint servers. The vulnerability allows an attacker to upload a specially crafted SharePoint application package to escalate privileges and execute arbitrary code. When the server has been compromised the attacker accesses the domain controller to launch the ransomware attack. The vulnerability was addressed by Microsoft in security updates that were released in early 2019.
Activities
When Hello is executed it encrypts files and appends affected filenames with the .hello extension.
Remediation advice
Microsoft has released updates to address this vulnerability. Users and administrators are encouraged to review the following security advisories and apply the necessary updates:
- Microsoft Security Advisory CVE-2019-0604
- NCSC Alert: Microsoft SharePoint remote code vulnerability
A Snort signature also exists to detect exploitation against this vulnerability (Snort ID 49681).
If a device on your network becomes infected with ransomware it will begin encrypting files, which may also include remote files on network locations. The only guaranteed way to recover from a ransomware infection is to restore all affected files from their most recent backup. To limit the impact of a ransomware infection, NHS Digital advises that:
- Critical data is frequently saved in multiple backup locations.
- At least one backup is kept offline at any time (separated from live systems).
- Backups and incident recovery plans are tested to ensure that data can be restored when needed.
- User account permissions for modifying data are regularly reviewed and restricted to the minimum necessary.
- Infected systems are disconnected from the network and powered down as soon as practicable.
- Any user account credentials that may have been compromised should be reset on a clean device
- Where infected systems cannot be quarantined with confidence, then an affected organisation should disconnect from national networks to limit propagation.
Additionally, to prevent and detect an infection, NHS Digital advises that:
- Secure configurations are applied to all devices.
- Security updates are applied at the earliest opportunity.
- Tamper protection settings in security products are enabled where available.
- Obsolete platforms are segregated from the rest of the network.
- IT usage policies are reinforced by regular training to ensure all users know not to open unsolicited links or attachments.
- Multi-factor authentication (MFA) and lockout policies are used where practicable, especially for administrative accounts.
- Administrative accounts are only used for necessary purposes.
- Remote administration services use strongly encrypted protocols and only accept connections from authorised users or locations.
- Systems are continuously monitored, and unusual activity is investigated, so that a compromise of the network can be detected as early as possible.
Please note that NCSC maintains guidance for securely configuring a wide range of end user device (EUD) platforms. For further details refer to their end user device security guidance pages.
Indicators of compromise
Last edited: 12 February 2021 3:03 pm