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Objects > Security Profiles > Anti-Spyware Profile

You can attach an Anti-Spyware profile to a Security policy rule to detect connections initiated by spyware and various types of command-and-control (C2) malware installed on systems on your network. You can choose between two predefined Anti-Spyware profiles to attach to a Security policy rule. Each profile has a set of predefined rules (with threat signatures) organized by the severity of the threat; each threat signature includes a default action that is specified by Palo Alto Networks.
  • Default—The default profile uses the default action for every signature, as specified by the Palo Alto Networks content package when the signature is created.
  • Strict—The strict profile overrides the action defined in the signature file for critical, high, and medium severity threats, and sets it to the
    reset-both
    action. The default action is taken with low and informational severity threats.
  • You can also create custom profiles. You can, for example, reduce the stringency for Anti-Spyware inspection for traffic between trusted security zones, and maximize the inspection of traffic received from the internet, or traffic sent to protected assets such as server farms.
The following tables describe the Anti-Spyware profile settings:
Anti-Spyware Profile Settings
Description
Name
Enter a profile name (up to 31 characters). This name appears in the list of Anti-Spyware profiles when defining security policies. The name is case-sensitive and must be unique. Use only letters, numbers, spaces, hyphens, periods, and underscores.
Description
Enter a description for the profile (up to 255 characters).
Shared (
Panorama only
)
Select this option if you want the profile to be available to:
  • Every virtual system (vsys) on a multi-vsys firewall. If you clear this selection, the profile will be available only to the
    Virtual System
    selected in the
    Objects
    tab.
  • Every device group on Panorama. If you clear this selection, the profile will be available only to the
    Device Group
    selected in the
    Objects
    tab.
Disable override (
Panorama only
)
Select this option to prevent administrators from overriding the settings of this Anti-Spyware profile in device groups that inherit the profile. This selection is cleared by default, which means administrators can override the settings for any device group that inherits the profile.
Signature Policies Tab
Anti-Spyware rules allow you to define a custom severity and action to take on any threat, a specific threat name that contains the text that you enter, and/or by a threat category, such as adware.
Add
a new rule, or you can select an existing rule to and select
Find Matching Signatures
to filter threat signatures based on that rule.
Rule Name
Specify the rule name.
Threat Name
Enter
any
to match all signatures, or enter text to match any signature containing the entered text as part of the signature name.
Category
Choose a category, or choose
any
to match all categories.
Action
Choose an action for each threat. For a list of actions, see Actions in Security Profiles.
The
Default
action is based on the pre-defined action that is part of each signature provided by Palo Alto Networks. To view the default action for a signature, select
Objects
Security Profiles
Anti-Spyware
and
Add
or select an existing profile. Click the
Exceptions
tab and then click
Show all signatures
to see a list of all signatures and the associated
Action
.
For the best security, use the Action settings in the predefined
strict
profile.
Packet Capture
Select this option if you want to capture identified packets.
Select
single-packet
to capture one packet when a threat is detected, or select the
extended-capture
option to capture from 1 to 50 packets (default is 5 packets). Extended-capture provides more context about the threat when analyzing the threat logs. To view the packet capture, select
Monitor
Logs
Threat
, locate the log entry you are interested in, and then click the green down arrow in the second column. To define the number of packets to capture, select
Device
Setup
Content-ID
and then edit the Content-ID™ Settings.
If the action for a given threat is allow, the firewall does not trigger a Threat log and does not capture packets. If the action is alert, you can set the packet capture to single-packet or extended-capture. All blocking actions (drop, block, and reset actions) capture a single packet. The content package on the device determines the default action.
Enable extended-capture for critical, high, and medium severity events. Use the default extended-capture value of 5 packets, which provides enough information to analyze the threat in most cases. (Too much packet capture traffic may result in dropping packet captures.) Don’t enable extended-capture for informational and low severity events because it’s not very useful compared to capturing information about higher severity events and creates a relatively high volume of low-value traffic.
Severity
Choose a severity level (
critical
,
high
,
medium
,
low
, or
informational
).
Signature Exceptions Tab
Allows you to change the action for a specific signature. For example, you can generate alerts for a specific set of signatures and block all packets that match all other signatures. Threat exceptions are usually configured when false-positives occur. To make management of threat exceptions easier, you can add threat exceptions directly from the
Monitor
Logs
Threat
list. Ensure that you obtain the latest content updates so that you are protected against new threats and have new signatures for any false-positives.
Exceptions
Enable
each threat for which you want to assign an action or select
All
to respond to all listed threats. The list depends on the selected host, category, and severity. If the list is empty, there are no threats for the current selections.
Use IP Address Exemptions to add IP address filters to a threat exception. If IP addresses are added to a threat exception, the threat exception action for that signature overrides the action for a rule only when the signature is triggered by a session with a source or destination IP address that matches an IP address in the exception. You can add up to 100 IP addresses per signature. With this option, you do not have to create a new policy rule and new vulnerability profile to create an exception for a specific IP address.
Create an exception only if you are sure that a signature identified as spyware is not a threat (it is a false positive). If you believe you discovered a false positive, open a support case with TAC so Palo Alto Networks can analyze and fix the incorrectly identified signature. As soon as the issue is resolved, remove the exception from the profile.
DNS Policies Tab
The
DNS Policies
settings provide an additional method of identifying infected hosts on a network. These signatures detect specific DNS lookups for host names that have been associated with DNS-based threats.
You can configure specific DNS signature sources with separate policy actions, log severity level, and packet capture settings. Hosts that perform DNS queries for malware domains will appear in the botnet report. Additionally, you can specify sinkhole IPs in the
DNS Sinkhole Settings
if you are sinkholing malware DNS queries.
DNS Signature Source
Allows you to select the lists for which you want to enforce an action when a DNS query occurs. There are two default DNS signature policy options:
  • Palo Alto Networks Content
    —A local downloadable signature list that is updated through dynamic content updates.
  • DNS Security
    —A cloud-based DNS security service that performs pro-active analysis of DNS data and provides real-time access to the complete Palo Alto Networks DNS signature database.
    This service requires the purchase and activation of the DNS Security license in addition to a Threat Prevention license.
  • External Dynamic Lists
    —EDLs operating as a domain list can be used to enforce a specific action for a selection of domains, for example, as an alert list. By default, policy actions for domain lists are configured to Allow.
    An EDL allow list does not have precedence over the domain policy action specified under DNS Security. As a result, when there is a domain match to an entry in the EDL and a DNS Security domain category, the action specified under DNS Security is still applied, even when the EDL is explicitly configured with an action of allow. If you want to add DNS domain exceptions, either configure an EDL with an Alert action or add them to the
    DNS Domain/FQDN Allow List
    located in the
    DNS Exceptions
    tab.
By default, the locally-accessed Palo Alto Networks Content DNS signatures are sinkholed, while the cloud-based DNS Security is set to allow. If you want to enable sinkholing using DNS Security, you must configure the action on DNS queries to sinkhole. The default address used for sinkholing belongs to Palo Alto Networks (sinkhole.paloaltonetworks.com). This address is not static and can be modified through content updates on the firewall or Panorama.
Add
a new list and select the External Dynamic List of type Domain that you created. To create a new list, see Objects > External Dynamic Lists.
Log Severity
Allows you to specify the log severity level that is recorded when the firewall detects a domain matching a DNS signature.
Policy Action
Choose an action to take when DNS lookups are made to known malware sites. The options are
alert
,
allow
,
block
, or
sinkhole
. The default action for Palo Alto Networks DNS signatures is
sinkhole
.
The DNS sinkhole action provides administrators with a method of identifying infected hosts on the network using DNS traffic, even when the firewall is north of a local DNS server (for example, the firewall cannot see the originator of the DNS query). When a threat prevention license is installed and an Anti-Spyware profile is enabled in a Security Profile, the DNS-based signatures trigger on DNS queries directed at malware domains. In a typical deployment where the firewall is north of the local DNS server, the threat log identifies the local DNS resolver as the source of the traffic rather than the actual infected host. Sinkholing malware DNS queries solves this visibility problem by forging responses to the queries directed at malicious domains, so that clients attempting to connect to malicious domains (for command-and-control, for example) instead attempt connections to an IP address specified by the administrator. Infected hosts can then be easily identified in the traffic logs because any host that attempts to connect to the sinkhole IP are most likely infected with malware.
Enable DNS sinkhole when the firewall can’t see the originator of the DNS query (typically when the firewall is north of the local DNS server) so you can identify infected hosts. If you can’t sinkhole the traffic, block it.
Packet Capture
Select this option for a given source if you want to capture identified packets.
Enable packet capture on sinkholed traffic so you can analyze it and get information about the infected host.
DNS Sinkhole Settings
After sinkhole action is defined for a DNS signature source, specify an IPv4 and/or IPv6 address that will be used for sinkholing. By default, the sinkhole IP address is set to a Palo Alto Networks server. You can then use the traffic logs or build a custom report that filters on the sinkhole IP address and identify infected clients.
The following is the sequence of events that will occur when an DNS request is sinkholed:
Malicious software on an infected client computer sends a DNS query to resolve a malicious host on the Internet.
The client's DNS query is sent to an internal DNS server, which then queries a public DNS server on the other side of the firewall.
The DNS query matches a DNS entry in the specified DNS signature database source, so the sinkhole action will be performed on the query.
The infected client then attempts to start a session with the host, but uses the forged IP address instead. The forged IP address is the address defined in the Anti-Spyware profile DNS Signatures tab when the sinkhole action is selected.
The administrator is alerted of a malicious DNS query in the threat log, and can then search the traffic logs for the sinkhole IP address and can easily locate the client IP address that is trying to start a session with the sinkhole IP address.
DNS Exceptions Tab
The DNS signature exceptions allow you to exclude specific threat IDs from policy enforcement as well as specify domain/FQDN allow lists for approved domain sources.
To add specific threats that you want to exclude from policy, select or search for a
Threat ID
and click
Enable
. Each entry provides the threat
Threat ID
,
Name
, and
FQDN
of the object.
To
Add
a domain or FQDN allow list, provide the location of the allow list as well as an appropriate description.

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