CSAF Security Advisories and VEX Security Data🔗
Security Data Overview🔗
In the past, Red Hat published security advisory information using Common Vulnerability Reporting Framework (CVRF) and CVE information using the Open Vulnerability and Assessment Language (OVAL) format. As of July 10th,2024, Red Hat Product Security publishes CSAF files for every single Red Hat Security Advisory (RHSA) and VEX files for every single CVE record that is associated with the Red Hat portfolio in any way.
The Common Security Advisory Framework (CSAF) was originally published as an open standard by OASIS Open in November 2022. CSAF files provide a structured, machine-readable way of representing and sharing security advisory information across all software and hardware providers.
CSAF Security Advisories Overview🔗
Red Hat's CSAF security advisory files are always associated with an RHSA. A given security advisory may describe one or more product version(s) and one or more components, depending on the product type and update scope. The RHSA itself can also include updates to address one or more vulnerabilities. Red Hat's CSAF files are publicly available per RHSA here.
CSAF VEX Overview🔗
The CSAF standard acknowledges the need for different use cases and has therefore defined a variety of profiles. Each profile describes the necessary fields and information needed for that specific use case. Red Hat has adopted the Vulnerability Exploitability eXchange (VEX) profile, which is intended to provide the affected state of a vulnerability on a product or component.
Red Hat's VEX files are always associated with one CVE and include fix status information for all vulnerable packages and Red Hat products. Red Hat's VEX files are publicly available per CVE here.
Document Structure🔗
Although CSAF advisory and VEX files ultimately serve different purposes, both file types meet the CSAF machine-readable standard and use the VEX profile to convey security information. The CSAF standard includes three main sections: document metadata, a product tree and vulnerability metadata. The full document structure can be found here.
The following sections break down the information included in CSAF-VEX documents using the VEX file for CVE-2023-20593 as an example.
Document Metadata🔗
The document section contains general information about the published document itself including the CVE severity, vendor,
published date and revision history.
The aggregate_severity.text object displays the general CVE severity:
{
"aggregate_severity": {
"namespace": "https://access.redhat.com/security/updates/classification/",
"text": "moderate"
}
}
The following objects provide general information about the VEX file itself:
{
"category": "csaf_vex",
"csaf_version": "2.0",
"distribution": {
"text": "Copyright © Red Hat, Inc. All rights reserved.",
"tlp": {
"label": "WHITE",
"url": "https://www.first.org/tlp/"
}
},
"lang": "en",
"notes": [
{
"category": "legal_disclaimer",
"text": "This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original.",
"title": "Terms of Use"
}
]
}
Vendor information is represented in the publisher object:
{
"publisher": {
"category": "vendor",
"contact_details": "https://access.redhat.com/security/team/contact/",
"issuing_authority": "Red Hat Product Security is responsible for vulnerability handling across all Red Hat offerings.",
"name": "Red Hat Product Security",
"namespace": "https://www.redhat.com"
}
}
CVE ID, CVE publish date and CVE revision history:
id: Provides the official CVE ID.initial_release_date: Represents the date that the Red Hat first published information on the CVE.revision_history: Details any changes made to the CVE information published by Red Hat.
{
"id": "CVE-2023-20593",
"initial_release_date": "2023-07-25T06:30:00+00:00",
"revision_history": [
{
"date": "2023-07-25T06:30:00+00:00",
"number": "1",
"summary": "Initial version"
},
{
"date": "2024-04-18T04:20:20+00:00",
"number": "2",
"summary": "Current version"
},
{
"date": "2024-09-13T20:58:30+00:00",
"number": "3",
"summary": "Last generated version"
}
],
"status": "final",
"version": "3"
}
Product Tree🔗
The product_tree section identifies all affected Red Hat software, represents the nested
relationship of component to product and provides CPEs or PURLs depending on the affected layer. There are two main
objects in the “product_tree” object: branches and relationships.
Branches🔗
The parent branches object has one child object of the vendor category with the name set to "Red Hat". All
affected Red Hat products and components will be nested in that "branches" array. Compressed down, the parent branches
object would look like:
{
"branches": [
{
"branches": [],
"category": "vendor",
"name": "Red Hat"
}
]
}
All nested objects included in the branches object of the vendor category fall into the following subcategories:
product_family: Represents a general Red Hat product main stream and includes one or more nested objects of theproduct_namecategory.product_name: Represents a specific product release and is always nested under the correspondingproduct_familycategory.product_version: Represents a specific component. When displayed unnested, the component is not fixed yet and will not include a specific version number. Note: This will only be present in VEX files since CSAF files are per RHSA and will only include fixed components.architecture: Represents fixed components by their architecture and includes nested "product_version" objects. These "product_version" will be fixed and provide the specific version number.
Product Family and Product Name Examples🔗
The product_family category represents a general Red Hat product stream and includes one or
more nested objects of the product_name category that represents an individual release. The product_name object will
always include the name of the product, a product ID and a product identification helper in the form of a CPE.
In the example below, you can see that the product_family object is for Red Hat Enterprise Linux 6 and nested within
is the product_name object Red Hat Enterprise Linux 6 with the CPE "cpe:/o:redhat:enterprise_linux:6".
{
"branches": [
{
"category": "product_name",
"name": "Red Hat Enterprise Linux 6",
"product": {
"name": "Red Hat Enterprise Linux 6",
"product_id": "red_hat_enterprise_linux_6",
"product_identification_helper": {
"cpe": "cpe:/o:redhat:enterprise_linux:6"
}
}
}
],
"category": "product_family",
"name": "Red Hat Enterprise Linux 6"
}
Unfixed Product Versions (VEX only) Examples🔗
The product_version category includes information about a specific affected package. The product_version object will
always include the name of the component, a product ID and a product identification helper in the form of a
PURL. When
displayed unnested under an architecture object, the name attribute will not reference a specific version number
because these components are unfixed. Again, these unfixed product_version components will only be found in VEX files
since CSAF files always represent a released RHSA. The purl identifiers for unfixed content are only available for rpm, oci (container), and rpmmod (modular) purl content type.
In the example below, the unfixed kernel component's name is "kernel" and doesn't include a specific version number or an architecture format.
{
"category": "product_version",
"name": "kernel",
"product": {
"name": "kernel",
"product_id": "kernel",
"product_identification_helper": {
"purl": "pkg:rpm/redhat/kernel?arch=src"
}
}
}
Architecture and Fixed Product Versions🔗
Similarly to the product_family object, the architecture category represents a specific architecture for packages
and includes one or more product_version objects. As before, the product_version category will still include the same
information: the name of the component, a product ID and product identification helper in the form of a
PURL. However,
when product_versions are nested under architecture object, they are fixed components and the name attribute will
include a specific version number and the specific architecture format.
In the example below, you can see the fixed kernel component's name is "kernel-0:3.10.0-693.112.1.el7.src" which includes the specific version number "0:3.10.0-693.112.1.el7" and architecture format ".src".
{
"branches": [
{
"category": "product_version",
"name": "kernel-0:3.10.0-693.112.1.el7.src",
"product": {
"name": "kernel-0:3.10.0-693.112.1.el7.src",
"product_id": "kernel-0:3.10.0-693.112.1.el7.src",
"product_identification_helper": {
"purl": "pkg:rpm/redhat/kernel@3.10.0-693.112.1.el7?arch=src"
}
}
}
],
"category": "architecture",
"name": "src"
}
Relationships🔗
Also included in the product_tree section is a relationships object which is used by Red Hat to help represent
layered products. One or more relationship entries will be present for all product_version objects found in the
branches object. All of these objects are of the default_component_of category and include the full product
name and product ID (a combination of the product_name and the product_version), a reference to the component name
and a reference to the product name.
Continuing with the previous examples, we know that there should be at least one entry in the relationships object
that correlates to the product_version object for kernel. Looking at the VEX file, there are actually four entries for
kernel, all which relate to the different product_name objects from before. The below is the specific entry as it
relates to Red Hat Enterprise Linux 6.
Here you can see that the full_product_name includes a name and a product_id which are the combination of the product,
Red Hat Enterprise Linux 6, and the component, kernel. The product_reference will always refer to the component's name
while the relates_to_product_reference will refer to the product name.
{
"category": "default_component_of",
"full_product_name": {
"name": "kernel as a component of Red Hat Enterprise Linux 6",
"product_id": "red_hat_enterprise_linux_6:kernel"
},
"product_reference": "kernel",
"relates_to_product_reference": "red_hat_enterprise_linux_6"
}
For the fixed component kernel-0:3.10.0-693.112.1.el7.src, a relationship entry looks like:
{
"category": "default_component_of",
"full_product_name": {
"name": "kernel-0:3.10.0-693.112.1.el7.src as a component of Red Hat Enterprise Linux Server AUS (v. 7.4)",
"product_id": "7Server-7.4.AUS:kernel-0:3.10.0-693.112.1.el7.src"
},
"product_reference": "kernel-0:3.10.0-693.112.1.el7.src",
"relates_to_product_reference": "7Server-7.4.AUS"
}
Vulnerability Metadata🔗
The vulnerabilities section reports vulnerability metadata for the CVE and also contains a
product_status object that reports affected status and fix information for any product_id listed in the product_tree and a remediations
object.
General CVE Information🔗
Basic CVE information is represented using the following objects:
* cve: The official CVE ID.
* cwe: Information about the corresponding CWE, include the CWE ID and the name.
* discovery_date: The first reported date of the vulnerability. Note: This date can differ from the previously
mentioned initial_release_date if the CVE was coordinated under embargo.
{
"cve": "CVE-2023-20593",
"cwe": {
"id": "CWE-1239",
"name": "Improper Zeroization of Hardware Register"
},
"discovery_date": "2023-05-31T00:00:00+00:00"
}
Additional CVE information can be found in the notes object:
description: This category includes a written description of the CVE.summary: This category includes a short summary of the CVE.statement: This category includes a statement from Red Hat on the CVE, when applicable (not present in the example).general: This category includes a general statement on the applicability of CVSS scores.{ "notes": [ { "category": "description", "text": "A flaw was found in hw, in “Zen 2” CPUs. This issue may allow an attacker to access sensitive information under specific microarchitectural circumstances.", "title": "Vulnerability description" }, { "category": "summary", "text": "hw: amd: Cross-Process Information Leak", "title": "Vulnerability summary" }, { "category": "general", "text": "The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.", "title": "CVSS score applicability" } ] }
A CVE can have a single CVSS score that is associated to all products and components in the VEX file or there can be different CVSS score metrics for different subset of products and components (per component Severity and CVSS metadata)
All CVSS scores associated with the CVE will have entries included scores object:
cvss_v3: Includes attributes for each CVSS base value, the complete CVSS vector string and the version of CVSS that is used.products: Includes all product IDs, both for products and components, that are represented by the scores in thecvss_v3object.{ "scores": [ { "cvss_v3": { "attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "NONE", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N", "version": "3.1" }, "products": [] } ] }
Similarly to CVSS scores, a CVE can have one severity impact value that represents all products and components in the VEX file or there can be different severity impact values for different subset of products and components (per component Severity and CVSS metadata).
All severity impact values with the CVE will have entires includes in the threats object:
category: The "impact" value identifies that the following information is the severity impact value of a CVE.details: Reports the appropriate Red Hat Severity Rating for the associatedproduct_ids.product_ids: Includes all product IDs, both for products and components, that have the severity rating in thedetailsobject.{ "threats": [ { "category": "impact", "details": "Moderate", "product_ids": [] } ] }
Additional CVE resources are described in the references object:
category: Either of the type "self" or "external".summary: A summary of the provided resource.url: A link to the resource.{ "references": [ { "category": "self", "summary": "Canonical URL", "url": "https://access.redhat.com/security/cve/CVE-2023-20593" }, { "category": "external", "summary": "RHBZ#2217845", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2217845" }, { "category": "external", "summary": "https://www.cve.org/CVERecord?id=CVE-2023-20593", "url": "https://www.cve.org/CVERecord?id=CVE-2023-20593" }, { "category": "external", "summary": "https://nvd.nist.gov/vuln/detail/CVE-2023-20593", "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-20593" }, { "category": "external", "summary": "https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=522b1d69219d8f083173819fde04f994aa051a98", "url": "https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=522b1d69219d8f083173819fde04f994aa051a98" }, { "category": "external", "summary": "https://www.amd.com/en/resources/product-security/bulletin/amd-sb-7008.html", "url": "https://www.amd.com/en/resources/product-security/bulletin/amd-sb-7008.html" } ] }
Product Fix Status🔗
The product_status includes the following fix statuses:
fixed: Contains the same fixed component versions and other details (product_tree objects) that the are reported fixed for a given CVEknown_affected: Confirmation that the specific component and product is affected by a particular CVEknown_not_affected: Confirmation that the specific component and product is not affected by a particular CVEunder_investigation: Information that the Red Hat Product Security team is verifying the applicability and impact of a specific CVE to the specific component and product
Compressed down, a product_status object that included products of each category, would look like:
{
"product_status": {
"fixed": [],
"known_affected": [],
"known_not_affected": [],
"under_investigation": []
}
}
fixed and optionally known_not_affected category if in the released RHSA there are more components and not all were vulnerable to the particular CVE id.
Continuing with our previous examples with CVE-2023-20593, the full product ID "red_hat_enterprise_linux_6:kernel"
can be found in the known_not_affected list:
{
"known_not_affected": [
"...",
"red_hat_enterprise_linux_6:kernel",
"red_hat_enterprise_linux_6:microcode_ctl"
]
}
Our other full product ID "7Server-7.4.AUS:kernel-0:3.10.0-693.112.1.el7.src" can be found in the fixed list:
{
"fixed": [
"...",
"7Server-7.4.AUS:kernel-0:3.10.0-693.112.1.el7.src",
"7Server-7.4.AUS:kernel-0:3.10.0-693.112.1.el7.x86_64",
"..."
]
}
Remediations🔗
The remediations object provides additional information about the previously identified product status. The following
remediations status are available per product_status category:
fixedvendor_fix: For all the product IDs with a fixed product status there will be a corresponding entry in the remediations object that correlates each full product ID to the correct RHSAs. The RHSA can be determined by theurlfield.- Details: "Fixed"
- URL: Link to the RHSA
workaround: If a mitigation exists, it applies to all components regardless of their fix state.Details: "Mitigation"
known_affectedno_fix_planned: Will include any product IDs with the known affected product status that will not be fixed by Red Hat, either because it is out of support scope or the engineering team has decided not to fix it for other reasons.- Details: "Will not fix" or "Out of support scope"
none_available: Will include any product IDs with the known affected product status that are either still reported affected, meaning a fix is likely in progress, or deferred, which may be fixed at a future date.- Details: "Affected" or "Deferred"
workaround: If a mitigation exists, it applies to all components regardless of their fix state.- Details: "Mitigation"
known_not_affected: There are no remediation objects for the known not affected status since it is implicitly assumed that there are no remediations needed if the product and component are not affected.under_investigation: There are no remediation objects for the under investigation status since it is implicitly assumed that no remediations exist since we are still investigating the vulnerability.
Note: As with the product_status object, there may not be a remediations entry for every category. Additionally,
in VEX files, there may be more than one vendor_fix object if more than one RHSA released fixes for the CVE. In the
CSAF files, the only remediations category present will be one vendor_fix object that maps to the RHSA that
the CSAF file represents.
Following our two previous kernel examples, we can see that for the unfixed kernel component
"red_hat_enterprise_linux_6:kernel" there is no entry in the remediation section. This is expected behavior because
it was listed in the known_not_affected product status and therefore no remediation is needed.
For our fixed kernel component "7Server-7.4.AUS:kernel-0:3.10.0-693.112.1.el7.src", there are two remediation entries. One represents the vendor fix that was released and the other represents that there is a reported mitigation for this CVE.
{
"category": "vendor_fix",
"details": "For details on how to apply this update, which includes the changes described in this advisory, refer to:\n\nhttps://access.redhat.com/articles/11258\n\nThe system must be rebooted for this update to take effect.",
"product_ids": [
"7Server-7.4.AUS:kernel-0:3.10.0-693.112.1.el7.src",
"7Server-7.4.AUS:kernel-0:3.10.0-693.112.1.el7.x86_64",
"..."
]
}
{
"category": "workaround",
"details": "Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.",
"product_ids": [
"...",
"7Server-7.4.AUS:kernel-0:3.10.0-693.112.1.el7.src",
"7Server-7.4.AUS:kernel-0:3.10.0-693.112.1.el7.x86_64",
"..."
]
}
Additional Questions or Concerns🔗
Red Hat is committed to continually improving our security data; any future changes to the data itself or the format of the files are tracked in the Red Hat Security Data Changelog.
Please contact Red Hat Product Security with any questions regarding security data at secalert@redhat.com or file an issue in the public SECDATA Jira project.