Prisma Cloud Administrator’s Guide (Compute)
    : Vulnerability Management Policies
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    Prisma Cloud Administrator’s Guide (Compute)

    Vulnerability Management Policies

    Table of Contents

    Vulnerability Management Policies

    Vulnerability policies are composed of discrete rules. Rules declare the actions to take when vulnerabilities are found in the resources in your environment. They also control the data surfaced in Prisma Cloud Console, including scan reports and Radar visualizations.
    Rules let you target segments of your environment and specify actions to take when vulnerabilities of a given type are found. For example,
    When there is no matching rule for vulnerability scanning on specific resources such as an image or a function, Prisma Cloud generates alerts on all vulnerabilities that are found.
    There are separate vulnerability policies for containers, hosts, and serverless functions. Host and serverless rules offer a subset of the capabilities of container rules, the big difference being that container rules support blocking.
    You can scope the vulnerabilities policies by collections and by package types.

    Create Vulnerability Rules

    Prisma Cloud ships with a simple default vulnerability policy for containers, hosts, and serverless functions. These policies have a rule named Default - alert all components, which sets the alert threshold to low. With this rule, all vulnerabilities in images, hosts, and functions are reported.
    As you build your policy, you create rules that filter out insignificant information, such as low-severity vulnerabilities, and surface vital information, such as critical vulnerabilities.
    Rule order is important. Prisma Cloud evaluates the rule list from top to bottom until it finds a match based on the object filters.
    By default, Prisma Cloud optimizes resource usage by only scanning images with running containers. Therefore, you might not see a scan report for an image when it is first pulled into your environment unless it’s been run. Note that images for short-lived containers are not scanned. To scan all images on the hosts (except CRI-O and containerd images) in your environment, go to
    Manage > System > Scan
    , set
    Only scan images with running containers
     to
    Off
    , and
    Save
    .
    When
    Only scan images with running containers
     is turned off, the image details show the start time when the Defender first reads the image. This is applicable for all images (deployed and not deployed), except CRI-O and containerd images.
    To create a vulnerability rule:
    1. Open Console.
    2. Go to
      Defend > Vulnerabilities > {Images | Hosts | Functions}
      .
    3. Select
      Add rule
      .
    4. Enter a
      Rule name
       and configure the rule. Configuration options are discussed in the following sections.
    5. Save
       the configuration.
    6. Go to
      Monitor > Vulnerabilities
       to view the scan reports.

    Severity-based Actions

    Vulnerability rules let you specify alert, block, or fail triggers based on severity thresholds. You can scope these rules based on collections and per-package type for granularity.
    For the package type, you can only set alert or block severity thresholds.
    The Severity-based actions let you establish quality gates in the CD segment of your continuous integration (CI) continuous deployment (CD) pipeline.
    The Severity threshold can be set at different values.
    Setting the alert threshold to off allows all vulnerabilities for the resources in scope (as defined by your filters). Practically, resource nodes in Radar turn green (no issues to report), and scan reports are empty (no issues to report).
    When you create a blocking rule, Defender automatically installs itself as the final arbiter of all container lifecycle commands. This way, the Defender can assess a Docker command, your current policy, and the status of an image before either forwarding the command to runC for execution or blocking it altogether.
    In
    Rule type
    , you can define the severity threshold for
    Generic
     collection or per-package type when you select
    Package type specific
     rule. When you define vulnerabilities policies by package type, you can monitor alerts at a granular level and focus on vulnerabilities in specific packages.
    • You can add any of the available package types: Jar, Python, Nodejs, Gem, Go, and App.
    • The package type severity thresholds apply to all workload types - deployed images, CI Images, hosts, VM images, functions, and CI Functions.
    • You can select all, multiple, or a single package type. The default rule applies to all package types.
    • Each package type should have a unique threshold, you cannot define different thresholds for the same package type.

    Risk Factors-based Actions

    For deployed and CI images, you can trigger different actions such as alert, block, and fail based on risk factors - "Exploit in the wild" and "Exploit POC". All the vulnerabilities that match any severity threshold or the risk factors will be listed in the scan results under
    Monitor > Vulnerabilities > Images > Deployed/Registries/CI
    . For example, you can set an alert on the vulnerabilities with severity high and critical, and choose "exploit in the wild" so you will be also alerted on any vulnerability with this risk factor.
    Image scan failed due to vulnerability policy violations by severity or by risk factors:
    • Each risk factor can be selected once per alert or block notification.
    • Setting the alert threshold to off allows all vulnerabilities for the resources in scope (as defined by your filters). Practically, resource nodes in Radar turn green (no issues to report), and scan reports are empty (no issues to report).

    Exclude Base Image Vulnerabilities

    Enable
    Exclude base image vulnerabilities
     to ignore the vulnerabilities introduced by base images from being displayed on the monitor scan results. To use this feature, you need to first specify the base image under
    Monitor > Vulnerabilities > Images > Base images
    .
    Prisma Cloud does not support base image filtering for the images that are built using kaniko, owing to an issue in kaniko that filters out the vulnerabilities from the whole application.

    Scope

    The scope field lets you target the rule to specific resources in your environment. The scope of a rule is defined by referencing one or more collections. By default, the scope is set to
    All
     collection, which applies the rule globally. For more information about creating and managing collections, see here.

    Vendor Fixes

    Rules can be applied conditionally, depending on whether vendor fixes are available. For example, you could tune your policy to block the deployment of containers with a critical vulnerability only if the vulnerable package has an update that resolves the issue. Otherwise, the deployment would be allowed to proceed.
    Some vulnerabilities have a vendor status of "Will not fix". This status is applied when vendors don’t intend to resolve a vulnerability because it poses no significant risk to your environment.

    Rule Exceptions

    You can configure Prisma Cloud to:
    • Alert, block, or fail on specific CVEs or tags (deny).
    • Ignore specific CVEs or tags (allow).
    Under
    Advanced settings
    , create a list of vulnerabilities and tags and specify how the scanner should handle them. Leaving the expiration date blank enforces the action until the CVE or tag is removed from the list. If you set an expiration date, and the current date is later than the expiration date, the scanner ignores the directive. The CVE or tag remains on the list even if it’s expired. It must be manually removed. Notice that for tag exceptions, in case of a conflict (a vulnerability with two tags or more that have different actions in the rule exceptions) there’s no guarantee what action will apply.

    Custom Terminal Output

    Prisma Cloud lets you create rules that block access to resources or block the deployment of vulnerable containers. For example, you might create a rule that blocks the deployment of any image that has critical severity vulnerabilities. By default, when you try to run a vulnerable image, Prisma Cloud returns a terse response:
    $ docker run -it ubuntu:14.04 sh
docker: Error response from daemon: [Prisma Cloud] Image operation blocked by policy: (sdf), has 44 vulnerabilities, [low:25 medium:19].
    To help the operator better understand how to handle a blocked action, you can enhance Prisma Cloud’s default response by:
    • Appending a custom message to the default message. For example, you could tell operators where to go to open a ticket.
    • Configuring Prisma Cloud to return an itemized list of compliance issues rather than just a summary. This way, the operator does not need to contact the security team to determine which issues are preventing deployment. They are explicitly listed in the response.
    When terminal output verbosity is set to
    Detailed
    , the response looks as follows:
    $ docker run -it ubuntu:14.04 sh
docker: Error response from daemon: [Prisma Cloud] Image operation blocked by policy: (sdf), has 44 vulnerabilities, [low:25 medium:19].
Image          ID       CVE             Package   Version             Severity   Status
=====          ==       ===             =======   =======             ========   ======
ubuntu:14.04   4333f1   CVE-2017-2518   sqlite3   3.8.2-1ubuntu2.1    medium     deferred
ubuntu:14.04   4333f1   CVE-2017-6512   perl      5.18.2-2ubuntu1.1   medium     needed
.
.
.

    Grace Period

    Grace periods temporarily override the blocking action of a rule when new vulnerabilities are found. Grace periods give you time to address a vulnerability without compromising the availability of your app. You can configure a uniform grace period for all severities or provide different settings for each severity.
    When grace periods are configured, alerts trigger as normal, notifying you that a vulnerability exists in your environment. The block action is suppressed for the number of days specified, giving you time to mitigate the vulnerability.
    The start time for the grace period is the date the vulnerability was identified by the Intelligence Stream (IS), known as the "fix date". The end time is the fixed date plus the number of days configured for the grace period. For any feed collected by IS that does not provide a fix date for CVE, Prisma Cloud Compute will determine the fix date as the date when the fix for the CVE was first seen by the Intelligence Stream. Therefore, the calculation for the grace period will now start with the date on which the CVE fix was seen on the Intelligence Stream and not the CVE publish date.
    For example, if a CVE was first discovered without a fix, and a fix was released later, the grace period for fixing the CVE would start from the date the fix was published, even though the vendor feed didn’t provide us with an explicit fix date.
    For the feeds that do provide a fix date for the CVEs (such as RHEL), the fix date will always be determined as the fix date provided by the vendor, and the grace period will be calculated using this fix date.
    The Consoles from older versions will also support the change for CVEs with no fix date provided by the vendor, since the change is done on the Intelligence Stream (IS) side which supports all the Consoles.
    The following diagram shows how Prisma Cloud Defender responds to a vulnerability discovered in your environment. Assume you have a vulnerability rule that blocks the deployment of any image with critical vulnerabilities, and the grace period is 30 days.
    • T
      1
       — The image has passed the security gates in your CI pipeline. It has no critical vulnerabilities, so it’s pushed to the registry.
    • T
      1
       - T
      2
       — The orchestrator runs the image in your cluster. The image has no critical vulnerabilities, so Defender allows it to run.
    • T
      2
       — Prisma Cloud Intelligence Stream acquires new threat data that identifies a critical vulnerability in the image. The package vendor released a fix as soon as the vulnerability was disclosed. In the next scan (by default, scans run every 24 hours), Prisma Cloud reports the vulnerability, and raises an alert if alerts are configured in the vulnerability rule.
    • T
      2
       - T
      grace_period
       — Prisma Cloud temporarily overrides the block rule, while the dev team addresses the vulnerability. The orchestrator can continue to pull copies of the image into your environment and run it.
    • T
      grace_period
       — Grace period expires. If the vulnerability has not been fixed yet, Prisma Cloud blocks any new deployments of the image from this time forward.
    Grace periods are a policy setting that’s available for all components that enforce vulnerability policy, namely Defender, twistcli, and the Jenkins plugin. In order to surface the issue as early as possible in the development lifecycle, you can specify a grace period in the CI pipeline. For example, this control would let you fail image builds that have critical vulnerabilities that were fixed over 30 days ago.
    The Grace period is disabled when the vulnerabilities are blocked by risk factors.

    Configure Grace Period

    You can configure grace periods for block actions (deployed images) and fail builds (CI images).
    1. In Console, go to
      Defend > Vulnerabilities > Images > Deployed/CI
      .
    2. Select an existing rule or select
      Add rule
       to create a new rule.
    3. Enter a
      Rule name
      ,
      Notes
      , and
      Scope
      .
    4. Select the
      Rule type
       to be
      Generic
       or
      Package type specific
      .
    5. Select the desired Alert/Block/Failure threshold based on Severity/Risk factors.
      The failure or block threshold must be equal to or greater than the alert threshold. You must define a failure/block threshold to configure grace period.
      1. Configure
        Block grace period
        :
        1. Select if you want to define a common grace period for
          All severities
           or define different grace periods
          By severity
           (Critical, High, Medium, and Low) type.
        2. Enter the number of grace period days.
          Note: In
          By severity
           grace period you can specify the number of days only for the severities that are configured to be failed or blocked in the severity threshold. The default value is 0.
          Note: The Grace period is disabled when the vulnerabilites are blocked by risk factors.

    Elapsed Time

    All scan reports show whether a vulnerability has been fixed (fix status) and when it was fixed (fix date), and the time remaining in the grace period. Scan reports are available from the:
    • Console UI.
    • Console UI as a CSV download.
    • API (JSON or CSV).
    • Jenkins plugin.
    • twistcli.
    The following example screenshot shows how the status of grace periods is displayed. Grace periods are either still in force or expired. For grace periods in force, the number of days remaining in the grace period is displayed. For grace periods that have expired, the number of days since they expired is displayed. Scan reports for running images can be retrieved from
    Monitor > Vulnerabilities > Images > Deployed
    .
    The following screenshot shows how the data is represented in the CSV scan report:

    Blocking Based on Vulnerability Severity

    This example shows you how to create and test a rule that blocks the deployment of images with critical or high-severity vulnerabilities.
    1. In Console, go to
      Defend > Vulnerabilities > Images > Deployed
      .
    2. Select
      Add rule
       and configure the rule.
      1. Target the rule to a specific image. In
        Scope
        , for example, select a collection with
        Images
        nginx*
        .
      2. Set both
        Alert
         and
        Block
        Severity threshold
         to
        High
        .
    3. Select
      Save
      .
    4. Validate your policy by pulling down the nginx image and running it.
      1. SSH to a host protected by Defender.
      2. Pull the nginx:1.14 image.
        $ docker pull nginx:1.14
      3. Run the nginx image.
        $ docker run -it nginx:1.14 /bin/sh
docker: Error response from daemon: oci runtime error: [Prisma Cloud] Image operation blocked by policy: my-rule, has 7 vulnerabilities, [high:7].
      4. Review the scan report for nginx:1.14. Go to
        Monitor > Vulnerabilities > Images
        , and click on the entry for nginx:1.14. You’ll see several high-severity vulnerabilities.
        By default, Prisma Cloud optimizes resource usage by only scanning images with running containers. Therefore, you won’t see a scan report for nginx until it’s run.
      5. Review the audit (alert) for the block action. Go to
        Monitor > Events
        , then click on
        Docker
        .

    Blocking Specific CVEs

    This example shows you how to create and test a rule that blocks images with a specific CVE.
    1. In Console, go to
      Defend > Vulnerabilities > Images
      .
    2. Click
      Add rule
      .
      1. Enter a
        Rule name, such as *my-rule2
        .
      2. Click
        Advanced settings
        .
      3. In
        Exceptions
        , click
        Add Exception
        .
      4. In
        CVE
        , enter
        CVE-2018-8014
        .
        You can find specific CVE IDs in the image scan reports. Go to
        Monitor > Vulnerabilities > Images
        , select an image, then click
        Show details
         in each row.
      5. In
        Effect
        , select
        Block
        .
      6. Click
        Add
        .
      7. Click
        Save
        .
    3. Try running an image with the CVE that you’ve explicitly denied.
      $ docker run -it imiell/bad-dockerfile:latest /bin/sh
docker: Error response from daemon: oci runtime error: [Prisma Cloud] Image operation blocked by policy: my-rule2, has specific CVE CVE-2018-8014

    Ignoring Specific CVEs

    Follow the same procedure as above, but set the action to
    Ignore
     instead of
    Block
    . This will allow any CVE ID that you’ve defined in the rule, and lets you run images containing those CVEs in your environment.

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