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https://github.com/flyingcircusio/vulnix

Vulnerability (CVE) scanner for Nix/NixOS.
https://github.com/flyingcircusio/vulnix

cve nix nixos security vulnerabilities vulnerability

Last synced: 3 months ago
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Vulnerability (CVE) scanner for Nix/NixOS.

Awesome Lists containing this project

README 

        
New maintainer needed! See https://github.com/flyingcircusio/vulnix/issues/87

for details.



Nix(OS) vulnerability scanner

=============================



This is a utility that validates a Nix store for any packages that are

reachable from live paths and likely to be affected by vulnerabilities

listed in the NVD.



It implements a CLI utility to inspect the current status and a

monitoring integration for Sensu.



Example output



.. code:: text



  2 derivations with active advisories



  ------------------------------------------------------------------------

  binutils-2.31.1



  /nix/store/zc1lbkaf9l9hlsp1jdiq3si56nsglymh-binutils-2.31.1.drv

  CVE                                                CVSSv3

  https://nvd.nist.gov/vuln/detail/CVE-2018-1000876  7.8

  https://nvd.nist.gov/vuln/detail/CVE-2018-20657    7.5

  https://nvd.nist.gov/vuln/detail/CVE-2018-20712    6.5



  ------------------------------------------------------------------------

  libssh2-1.9.0



  /nix/store/mfpfclry68r4sv4mcc9hb88z0lb9jk1c-libssh2-1.9.0.drv

  CVE                                                CVSSv3

  https://nvd.nist.gov/vuln/detail/CVE-2019-17498    8.1



Theory of operation

-------------------



``vulnix`` pulls all published CVEs from NIST_ and caches them locally. It

matches name and version of all derivations referenced from the command line

against known CVE entries. A *whitelist* is used to filter out unwanted results.



Matching Nix package names to NVD products is currently done via a coarse

heuristic. First, a direct match is tried. If no product can be found,

variations with lower case and underscore instead of hyphen are tried. It is

clear that this mapping is too simplistic and needs to be improved in future

versions.



System requirements

-------------------



- Depends on common Nix tools like ``nix-store``. These are expected to be in

  $PATH.

- Depends on being able to interact with the Nix store database

  (/nix/var/nix/db). This means that it must either run as the same user that

  owns the Nix store database or ``nix-daemon`` must be active.

- Parses ``*.drv`` files directly. Tested with Nix >=1.10 and 2.x.

- It refuses to work without some locale environment settings. Try ``export

  LANG=C.UTF-8`` if you see encoding errors.



Usage Example

=============



- What vulnerabilities are listed for my current system



.. code:: shell



  vulnix --system



- Check ``nix-build`` output together with its transitive closure



.. code:: shell



  vulnix result/



- Check all passed derivations, but don't determine requisites



.. code:: shell



  vulnix -R /nix/store/*.drv



- JSON output for machine post-processing



.. code:: shell



  vulnix --json /nix/store/my-derivation.drv



See ``vulnix --help`` for a list of all options.



Whitelisting

============



``vulnix`` output may contain false positives, unfixable packages or stuff which

is known to be addressed. The *whitelist* feature allows to exclude packages

matching certain criteria.



Usage

-----



Load whitelists from either local files or HTTP servers



.. code:: shell



  vulnix -w /path/to/whitelist.toml \

         -w https://example.org/published-whitelist.toml



Syntax

------



Whitelists are TOML_ files which contain the package to be filtered as section

headers, followed by further per-package options.



Section headings - package selection

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^



Exclude a package at a specific version



.. code:: toml



  ["openjpeg-2.3.0"]



Exclude a package regardless of version (additional CVE filters may apply, see

below)



.. code:: toml



  ["openjpeg"]



Exclude all packages (see below for CVE filters, again)



.. code:: toml



  ["*"]



Options

^^^^^^^



cve

  List of CVE identifiers to match. The whitelist rule is valid as long as the

  detected CVEs are a subset of the CVEs listed here. If additional CVEs are

  detected, this whitelist rule is not effective anymore.



until

  Date in the form "YYYY-MM-DD" which confines this rule's lifetime. On the

  specified date and later, this whitelist rule is not effective anymore.



issue_url

  URL or list of URLs that point to any issue tracker. Informational only.



comment

  String or list of strings containing free text. Informational only.



Examples

--------



Create a ticket on your favourite issue tracker. Estimate the time to get the

vulnerable package fixed. Create whitelist entry:



.. code:: toml



  ["ffmpeg-3.4.2"]

  cve = ["CVE-2018-6912", "CVE-2018-7557"]

  until = "2018-05-01"

  issue_url = "https://issues.example.com/29952"

  comment = "need to backport patch"



This particular version of ffmpeg will be left out from reports until either

another CVE gets published or the specified date is reached.



CVE patch auto-detection

========================



``vulnix`` will inspect derivations for patches which supposedly fix specific

CVEs. When a patch filename contains one or more CVE identifiers, these will not

reported anymore. Example Nix code:



.. code:: nix



  {

    patches = [ ./CVE-2018-6951.patch ];

  }



Patches which fix multiple CVEs should name them all with a non-numeric

separator, e.g. ``CVE-2017-14159+CVE-2017-17740.patch``.



Auto-detection even works when patches are pulled via ``fetchpatch`` and friends

as long as there is a CVE identifier in the name. Example:



.. code:: nix



  {

    patches = [

      (fetchpatch {

        name = "CVE-2018-9055.patch";

        url = http://paste.opensuse.org/view/raw/330751ce;

        sha256 = "0m798m6c4v9yyhql7x684j5kppcm6884n1rrb9ljz8p9aqq2jqnm";

      })

    ];

  }



.. _NIST: https://nvd.nist.gov/vuln/

.. _TOML: https://github.com/toml-lang/toml/