PH_Rule_PolicyViolation_9
Enabled
Detects VNC from Internet, which is defined as anything outside the Internal network. Please make sure that the Internal network definition is correct to avoid false positives
9
Security
Lateral Movement
Lateral Movement consists of techniques that adversaries use to enter and control remote systems on a network. Following through on their primary objective often requires exploring the network to find their target and subsequently gaining access to it. Reaching their objective often involves pivoting through multiple systems and accounts to gain. Adversaries might install their own remote access tools to accomplish Lateral Movement or use legitimate credentials with native network and operating system tools, which may be stealthier.
https://attack.mitre.org/tactics/TA0008T1021.005
Remote Services: VNC
Adversaries may use Valid Accounts to remotely control machines using Virtual Network Computing (VNC). The adversary may then perform actions as the logged-on user.
https://attack.mitre.org/techniques/T1021/005T1133
External Remote Services
Adversaries may leverage external-facing remote services to initially access and/or persist within a network. Remote services such as VPNs, Citrix, and other access mechanisms allow users to connect to internal enterprise network resources from external locations. Access to Valid Accounts to use the service is often a requirement, which could be obtained through credential pharming or by obtaining the credentials from users after compromising the enterprise network.
https://attack.mitre.org/techniques/T1133T1219
Remote Access Software
An adversary may use legitimate desktop support and remote access software, such as Team Viewer, Go2Assist, LogMein, AmmyyAdmin, etc, to establish an interactive command and control channel to target systems within networks. These services are commonly used as legitimate technical support software, and may be allowed by application control within a target environment.
https://attack.mitre.org/techniques/T1219Application
FortiGate via Syslog or Netflow, Checkpoint via Syslog or Netflow, Palo Alto via Syslog or Netflow
Correlation
No remediation guidance specified
If the following pattern or patterns match an ingested event within the given time window in seconds, trigger an incident.
600 seconds
If the following defined pattern/s occur within a 600 second time window.
VNC
This is the named definition of the event query, this is important if multiple subpatterns are defined to distinguish them.
This is the query logic that matches incoming events
srcIpAddr NOT IN (Group@PH_SYS_NETWORK_ENTERPRISE_INTERNAL_NET) AND destIpAddr IN (Group@PH_SYS_NETWORK_ENTERPRISE_INTERNAL_NET) AND srcIpPort >= 1024 AND ((destIpPort >= 5800 AND destIpPort <= 5820) OR (destIpPort >= 5900 AND destIpPort <= 5920) OR (destIpPort >= 6000 AND destIpPort <= 6020)) AND eventType IN (Group@PH_SYS_EVENT_PermitNetTraffic, Group@PH_SYS_EVENT_NetflowTraffic, Group@PH_SYS_EVENT_BiNetflowTraffic)
This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID
srcIpAddr,destIpAddr
This is most typically a numerical constraint that defines when the rule should trigger an incident
COUNT(*) >= 1
This section defines which fields in matching raw events should be mapped to the incident attributes in the resulting incident.
The available raw event attributes to map are limited to the group by attributes and the aggregate event constraint fields for each subpattern
srcIpAddr = VNC.srcIpAddr,
destIpAddr = VNC.destIpAddr