VNC (Virtual Network Computing) from the Internet
editVNC (Virtual Network Computing) from the Internet
editThis rule detects network events that may indicate the use of VNC traffic from the Internet. VNC is commonly used by system administrators to remotely control a system for maintenance or to use shared resources. It should almost never be directly exposed to the Internet, as it is frequently targeted and exploited by threat actors as an initial access or backdoor vector.
Rule type: query
Rule indices:
- auditbeat-*
- filebeat-*
- packetbeat-*
- logs-endpoint.events.*
Severity: high
Risk score: 73
Runs every: 5 minutes
Searches indices from: now-9m (Date Math format, see also Additional look-back time
)
Maximum alerts per execution: 100
References:
Tags:
- Elastic
- Host
- Network
- Threat Detection
- Command and Control
- Host
Version: 100 (version history)
Added (Elastic Stack release): 7.6.0
Last modified (Elastic Stack release): 8.5.0
Rule authors: Elastic
Rule license: Elastic License v2
Potential false positives
editVNC connections may be received directly to Linux cloud server instances but such connections are usually made only by engineers. VNC is less common than SSH or RDP but may be required by some work-flows such as remote access and support for specialized software products or servers. Such work-flows are usually known and not unexpected. Usage that is unfamiliar to server or network owners can be unexpected and suspicious.
Rule query
editevent.category:(network or network_traffic) and network.transport:tcp and destination.port >= 5800 and destination.port <= 5810 and not source.ip:( 10.0.0.0/8 or 127.0.0.0/8 or 169.254.0.0/16 or 172.16.0.0/12 or 192.0.0.0/24 or 192.0.0.0/29 or 192.0.0.8/32 or 192.0.0.9/32 or 192.0.0.10/32 or 192.0.0.170/32 or 192.0.0.171/32 or 192.0.2.0/24 or 192.31.196.0/24 or 192.52.193.0/24 or 192.168.0.0/16 or 192.88.99.0/24 or 224.0.0.0/4 or 100.64.0.0/10 or 192.175.48.0/24 or 198.18.0.0/15 or 198.51.100.0/24 or 203.0.113.0/24 or 240.0.0.0/4 or "::1" or "FE80::/10" or "FF00::/8" ) and destination.ip:( 10.0.0.0/8 or 172.16.0.0/12 or 192.168.0.0/16 )
Threat mapping
editFramework: MITRE ATT&CKTM
-
Tactic:
- Name: Command and Control
- ID: TA0011
- Reference URL: https://attack.mitre.org/tactics/TA0011/
-
Technique:
- Name: Remote Access Software
- ID: T1219
- Reference URL: https://attack.mitre.org/techniques/T1219/
-
Tactic:
- Name: Initial Access
- ID: TA0001
- Reference URL: https://attack.mitre.org/tactics/TA0001/
-
Technique:
- Name: Exploit Public-Facing Application
- ID: T1190
- Reference URL: https://attack.mitre.org/techniques/T1190/
Rule version history
edit- Version 100 (8.5.0 release)
-
- Formatting only
- Version 12 (8.4.0 release)
-
- Formatting only
- Version 11 (7.15.0 release)
-
- Formatting only
- Version 10 (7.14.0 release)
-
-
Updated query, changed from:
event.category:(network or network_traffic) and network.transport:tcp and destination.port >= 5800 and destination.port <= 5810 and not source.ip:( 10.0.0.0/8 or 127.0.0.0/8 or 169.254.0.0/16 or 172.16.0.0/12 or 192.168.0.0/16 or 224.0.0.0/4 or "::1" or "FE80::/10" or "FF00::/8" ) and destination.ip:( 10.0.0.0/8 or 172.16.0.0/12 or 192.168.0.0/16 )
-
- Version 8 (7.12.0 release)
-
- Formatting only
- Version 7 (7.11.2 release)
-
- Formatting only
- Version 6 (7.11.0 release)
-
-
Updated query, changed from:
event.category:(network or network_traffic) and network.transport:tcp and destination.port >= 5800 and destination.port <= 5810 and not source.ip:(10.0.0.0/8 or 127.0.0.0/8 or 172.16.0.0/12 or 192.168.0.0/16 or "::1") and destination.ip:(10.0.0.0/8 or 172.16.0.0/12 or 192.168.0.0/16)
-
- Version 5 (7.10.0 release)
-
- Formatting only
- Version 4 (7.9.0 release)
-
-
Updated query, changed from:
network.transport:tcp and destination.port >= 5800 and destination.port <= 5810 and not source.ip:(10.0.0.0/8 or 127.0.0.0/8 or 172.16.0.0/12 or 192.168.0.0/16 or "::1") and destination.ip:(10.0.0.0/8 or 172.16.0.0/12 or 192.168.0.0/16)
-
- Version 3 (7.7.0 release)
-
-
Updated query, changed from:
network.transport: tcp and (destination.port >= 5800 and destination.port <= 5810) and ( network.direction: inbound or ( not source.ip: (10.0.0.0/8 or 172.16.0.0/12 or 192.168.0.0/16) and destination.ip: (10.0.0.0/8 or 172.16.0.0/12 or 192.168.0.0/16) ) )
-
- Version 2 (7.6.1 release)
-
- Removed auditbeat-*, packetbeat-*, and winlogbeat-* from the rule indices.