Abnormal Recurring Communications to a Rare Domain

Synopsis

Field	Value
Activation Period	14 Days
Training Period	30 Days
Test Period	N/A (single event)
Deduplication Period	1 Day
Required Data	Requires one of the following data sources: Palo Alto Networks Firewall traffic Logs OR XDR Agent OR Third-Party Firewalls
Detector Tags	NDR C2 Detection
ATT&CK Tactic	Command and Control (TA0011)
ATT&CK Technique	Non-Application Layer Protocol (T1095)
Severity	Informational

Description

Abnormal communications were seen from an internal entity to a rare external domain. This could be a case of beaconing to a C2 Server.

Attacker's Goals

Communicate with malicious code running on your network enabling further access to the endpoint and network, performing software updates on the endpoint, or for taking inventory of infected machines.

Investigative actions

• Identify if the external domain belongs to a reputable organization or an asset used in a public cloud.
• Identify if the source of the traffic is malware. If the source of the traffic is a malicious file, Cortex XDR Analytics also raises a malware alert for the file on the endpoint. Malware may contact legitimate domain names, therefore check for unusual apps used or unusual ports or volumes accessed.
• View all related traffic generated by the suspicious process to understand the purpose.
• Look for other endpoints on your network that are also contacting the suspicious domain name.
• Examine file-system operations performed by the process that initiated the traffic and look for potential artifacts on infected endpoints.

Variations

Abnormal Recurring Communications to a Rare Domain With a Port Commonly Used by Attack Platforms

Synopsis

Field	Value
ATT&CK Tactic	Command and Control (TA0011)
ATT&CK Technique	Non-Application Layer Protocol (T1095)
Severity	Low

Description

Abnormal communications were seen from an internal entity to a rare external domain. This could be a case of beaconing to a C2 Server.

Attacker's Goals

Communicate with malicious code running on your network enabling further access to the endpoint and network, performing software updates on the endpoint, or for taking inventory of infected machines.

Investigative actions

• Identify if the external domain belongs to a reputable organization or an asset used in a public cloud.
• Identify if the source of the traffic is malware. If the source of the traffic is a malicious file, Cortex XDR Analytics also raises a malware alert for the file on the endpoint. Malware may contact legitimate domain names, therefore check for unusual apps used or unusual ports or volumes accessed.
• View all related traffic generated by the suspicious process to understand the purpose.
• Look for other endpoints on your network that are also contacting the suspicious domain name.
• Examine file-system operations performed by the process that initiated the traffic and look for potential artifacts on infected endpoints.

Abnormal Recurring Communications to a Rare Domain to a Suspicious Autonomous System (AS)

Synopsis

Field	Value
ATT&CK Tactic	Command and Control (TA0011)
ATT&CK Technique	Non-Application Layer Protocol (T1095)
Severity	Low

Description

Abnormal communications were seen from an internal entity to a rare external domain. This could be a case of beaconing to a C2 Server.

Attacker's Goals

Communicate with malicious code running on your network enabling further access to the endpoint and network, performing software updates on the endpoint, or for taking inventory of infected machines.

Investigative actions

• Identify if the external domain belongs to a reputable organization or an asset used in a public cloud.
• Identify if the source of the traffic is malware. If the source of the traffic is a malicious file, Cortex XDR Analytics also raises a malware alert for the file on the endpoint. Malware may contact legitimate domain names, therefore check for unusual apps used or unusual ports or volumes accessed.
• View all related traffic generated by the suspicious process to understand the purpose.
• Look for other endpoints on your network that are also contacting the suspicious domain name.
• Examine file-system operations performed by the process that initiated the traffic and look for potential artifacts on infected endpoints.

Abnormal Recurring Communications to a Rare Domain With an Abnormal Domain Suffix

Synopsis

Field	Value
ATT&CK Tactic	Command and Control (TA0011)
ATT&CK Technique	Non-Application Layer Protocol (T1095)
Severity	Informational

Description

Abnormal communications were seen from an internal entity to a rare external domain. This could be a case of beaconing to a C2 Server.

Attacker's Goals

Communicate with malicious code running on your network enabling further access to the endpoint and network, performing software updates on the endpoint, or for taking inventory of infected machines.

Investigative actions

• Identify if the external domain belongs to a reputable organization or an asset used in a public cloud.
• Identify if the source of the traffic is malware. If the source of the traffic is a malicious file, Cortex XDR Analytics also raises a malware alert for the file on the endpoint. Malware may contact legitimate domain names, therefore check for unusual apps used or unusual ports or volumes accessed.
• View all related traffic generated by the suspicious process to understand the purpose.
• Look for other endpoints on your network that are also contacting the suspicious domain name.
• Examine file-system operations performed by the process that initiated the traffic and look for potential artifacts on infected endpoints.

Abnormal Recurring Communications to a Rare Domain With a Less Common Port

Synopsis

Field	Value
ATT&CK Tactic	Command and Control (TA0011)
ATT&CK Technique	Non-Application Layer Protocol (T1095)
Severity	Low

Description

Abnormal communications were seen from an internal entity to a rare external domain. This could be a case of beaconing to a C2 Server.

Attacker's Goals

Communicate with malicious code running on your network enabling further access to the endpoint and network, performing software updates on the endpoint, or for taking inventory of infected machines.

Investigative actions

• Identify if the external domain belongs to a reputable organization or an asset used in a public cloud.
• Identify if the source of the traffic is malware. If the source of the traffic is a malicious file, Cortex XDR Analytics also raises a malware alert for the file on the endpoint. Malware may contact legitimate domain names, therefore check for unusual apps used or unusual ports or volumes accessed.
• View all related traffic generated by the suspicious process to understand the purpose.
• Look for other endpoints on your network that are also contacting the suspicious domain name.
• Examine file-system operations performed by the process that initiated the traffic and look for potential artifacts on infected endpoints.