RDP Sensitive Settings Changed

Description

Detects tampering of RDP Terminal Service/Server sensitive settings. Such as allowing unauthorized users access to a system via the 'fAllowUnsolicited' or enabling RDP via 'fDenyTSConnections', etc. Below is a list of registry keys/values that are monitored by this rule: - Shadow: Used to enable Remote Desktop shadowing, which allows an administrator to view or control a user's session. - DisableRemoteDesktopAntiAlias: Disables anti-aliasing for remote desktop sessions. - DisableSecuritySettings: Disables certain security settings for Remote Desktop connections. - fAllowUnsolicited: Allows unsolicited remote assistance offers. - fAllowUnsolicitedFullControl: Allows unsolicited remote assistance offers with full control. - InitialProgram: Specifies a program to run automatically when a user logs on to a remote computer. - ServiceDll: Used in RDP hijacking techniques to specify a custom DLL to be loaded by the Terminal Services service. - SecurityLayer: Specifies the security layer used for RDP connections.

Detection logic

Detection requirements

Platform: Windows
The rule states no platform. This is derived from the ATT&CK technique it maps to.
Log source product: windows
Log source category: registry_set

Known benign triggers

Some of the keys mentioned here could be modified by an administrator while setting group policy (it should be investigated either way)

References

Links the source published beside this detection. Reference is the link the source wrote, unmodified. Class is decided by this catalogue from the host and path, not stated by the source. Cited by counts published detections citing the same resource, including this one, and the sources beneath it count the repositories this catalogue ingests, which is not the same as independent research.
Reference	Class	Cited by
etutorials.org/Microsoft+Products/microsoft+windows+server+2003+terminal+services/Chapter+6+Registry/Registry+Keys+for+Terminal+Services/	Unclassified	3
woshub.com/rds-shadow-how-to-connect-to-a-user-session-in-windows-server-2012-r2/	Unclassified	3
admx.help/HKLM/SOFTWARE/Policies/Microsoft/Windows%20NT/Terminal%20Services	Unclassified	3
bazaar.abuse.ch/sample/6f3aa9362d72e806490a8abce245331030d1ab5ac77e400dd475748236a6cc81/	Unclassified	5
blog.sekoia.io/darkgate-internals/	Unclassified	2
blog.talosintelligence.com/understanding-the-phobos-affiliate-structure/	Threat report	2
github.com/redcanaryco/atomic-red-team/blob/02c7d02fe1f1feb0fc7944550408ea8224273994/atomics/T1112/T1112.md#atomic-test-63---disable-remote-desktop-anti-alias-setting-through-registry	Detection test	2
github.com/redcanaryco/atomic-red-team/blob/02c7d02fe1f1feb0fc7944550408ea8224273994/atomics/T1112/T1112.md#atomic-test-64---disable-remote-desktop-security-settings-through-registry	Detection test	2
github.com/redcanaryco/atomic-red-team/blob/dd526047b8c399c312fee47d1e6fb531164da54d/atomics/T1112/T1112.yaml#L790	Detection test	2
learn.microsoft.com/en-us/windows-hardware/customize/desktop/unattend/microsoft-windows-terminalservices-rdp-winstationextensions-securitylayer	Product documentation	2
threathunterplaybook.com/hunts/windows/190407-RegModEnableRDPConnections/notebook.html	Detection test	3
twitter.com/SagieSec/status/1469001618863624194?t=HRf0eA0W1YYzkTSHb-Ky1A&s=03	Social post	3
web.archive.org/web/20200929062532/https://blog.menasec.net/2019/02/threat-hunting-rdp-hijacking-via.html	Unclassified	3
www.trendmicro.com/en_us/research/25/i/unmasking-the-gentlemen-ransomware.html	Threat report	4

Detection rules

RDP Sensitive Settings Changed

Description

Detection logic

Detection requirements

Known benign triggers

MITRE ATT&CK mappings

References

From the source

Licence

Authorship

Detection rules