PH_RULE_SYSRVK_Botnet_Activity_Host
Enabled
A Fortinet product has detected Sysrv-K botnet Activity activity on a host
9
Security
Resource Development
Resource Development consists of techniques that involve adversaries creating, purchasing, or compromising/stealing resources that can be used to support targeting. Such resources include infrastructure, accounts, or capabilities. These resources can be leveraged by the adversary to aid in other phases of the adversary lifecycle, such as using purchased domains to support Command and Control, email accounts for phishing as a part of Initial Access, or stealing code signing certificates to help with Defense Evasion.
https://attack.mitre.org/tactics/TA0042T1584.005
Compromise Infrastructure: Botnet
Before compromising a victim, adversaries may compromise numerous third-party systems to form a botnet?that can be used during targeting. A botnet is a network of compromised systems that can be instructed to perform coordinated tasks. Instead of purchasing/renting a botnet from a booter/stressor service, adversaries may build their own botnet by compromising numerous third-party systems. Adversaries may also conduct a takeover of an existing botnet, such as redirecting bots to adversary-controlled C2 servers. With a botnet at their disposal, adversaries may perform follow-on activity such as large-scale Phishing or Distributed Denial of Service (DDoS).
https://attack.mitre.org/techniques/T1584/005Server
FortiClient via Syslog
Correlation
Check if the source is patched for the CVE associated with the event. If yes then remove the host from the network and patch immediately. If host is not scanned then determine if the host is running the affected version of the application. If yes then patch immediately, else it is likely a false positive.
If the following pattern or patterns match an ingested event within the given time window in seconds, trigger an incident.
300 seconds
If the following defined pattern/s occur within a 300 second time window.
sysrvk
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
eventType IN (Group@PH_SYS_EVENT_FortiClient_AV_Detected) AND (ipsSignatureId = 10090470 OR virusName = "Python/Sysrv_K.65EA!tr")
This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID
hostIpAddr
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
hostIpAddr=sysrvk.hostIpAddr,
incidentCount=sysrvk.COUNT(*)