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Detectionhightest

Publicly Accessible RDP Service

Detects connections from routable IPs to an RDP listener. Which is indicative of a publicly-accessible RDP service.

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Josh BrowerCreated Sat Aug 22Updated Wed Mar 131fc0809e-06bf-4de3-ad52-25e5263b7623network
Log Source
Zeek (Bro)rdp
ProductZeek (Bro)← raw: zeek
Servicerdp← raw: rdp
Detection Logic
Detection Logic1 selector
detection:
    selection:
        id.orig_h|cidr:
            - '::1/128'  # IPv6 loopback
            - '10.0.0.0/8'
            - '127.0.0.0/8'
            - '172.16.0.0/12'
            - '192.168.0.0/16'
            - '169.254.0.0/16'
            - '2620:83:8000::/48'
            - 'fc00::/7'  # IPv6 private addresses
            - 'fe80::/10'  # IPv6 link-local addresses
    # approved_rdp:
      # dst_ip:
        # - x.x.x.x
    condition: not selection # and not approved_rdp
False Positives

Although it is recommended to NOT have RDP exposed to the internet, verify that this is a) allowed b) the server has not already been compromised via some brute force or remote exploit since it has been exposed to the internet. Work to secure the server if you are unable to remove it from being exposed to the internet.

MITRE ATT&CK
Rule Metadata
Rule ID
1fc0809e-06bf-4de3-ad52-25e5263b7623
Status
test
Level
high
Type
Detection
Created
Sat Aug 22
Modified
Wed Mar 13
Author
Josh Brower
Path
rules/network/zeek/zeek_rdp_public_listener.yml
Raw Tags
attack.lateral-movementattack.t1021.001
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