vulnix 1.10.1
Scans a Nix store for derivations that are affected by vulnerabilities.
License: BSD-3-Clause
Keywords: security,nixos,nixpkgs,cve,nvd

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::

  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::

    vulnix --system

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

    vulnix result/

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

    vulnix -R /nix/store/*.drv

- JSON output for machine post-processing::

    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::

  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::

  ["openjpeg-2.3.0"]
  ...

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

  ["openjpeg"]

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

  ["*"]

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::

  ["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::

  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::

  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/


Building vulnix
===============

To create a development environment, use a Python 3 virtualenv::

    python3 -m venv .
    bin/pip install -e ".[test]"

Run tests::

    bin/py.test


Building man pages
==================

The provided makefile needs ronn_ to convert Markdown to troff::

    make -C doc

.. _ronn: https://rtomayko.github.io/ronn/


Changes
=======


1.10.1 (2022-02-06)
-------------------

- Expose CVE descriptions in both plain text and JSON output (#78).

- Fix compatibility issue due to pyyaml 6.0 in nixpkgs-unstable (#83).


1.10.0 (2021-07-16)
-------------------

- Extend `-f`/`--file` input. It now also accepts JSON input containing package
  names and applied patches.

- Wait rather than fail on concurrent invocations (#60).

- Ignore NVD entries without cpe23Uri (#68).

- Add `--profile` option to scan user environments (#72).

- Wait for lock on concurrent invocations instead of failing (#73).

- Improved tactics to find derivers (#74).

- Correctly handle the case when both an explicit version and version ranges are
  given in a NVD expression (#77).


1.9.6 (2020-07-02)
------------------

- Fix flake8 check (#64).

- Packaging: Improve keywords.


1.9.5 (2020-06-30)
------------------

- Add `-f` option which reads a list of derivations directly from a file.

- Exclude .tgz derivations by default.

- Change default mirror for NIST feeds (#61).

- Python 3.8 compatbility.


1.9.4 (2019-12-11)
------------------

- Fix "invalid package selector" bug.


1.9.3 (2019-11-26)
------------------

- Print CVSS scores by default.

- Fix reliability problem when migrating from old databases (#58).


1.9.2 (2019-11-16)
------------------

- Improve performance by pre-fetching all cached CPE configurations for each
  candidate vulnerability. This change requires to rebuild the ZODB database,
  which is done transparently.

- Fix bug that crashed vulnix when trying to extend existing whitelist entries
  with new CVEs (#57).


1.9.1 (2019-11-14)
------------------

- Fix packaging bug.


1.9.0 (2019-11-13)
------------------

- Pull NVD feeds from https://nvd.nist.gov/feeds/json/cve/1.1/ as XML feeds have
  been discontinued (#55).

- Print CVSS v3 base scores for each CVE. Order by descending CVSS score (#53).

- Evaluate version ranges in CPE entries.


1.8.2 (2019-06-17)
------------------

- Process package versions containing a hyphen properly (e.g., R versions)
  (#50).


1.8.1 (2019-04-08)
------------------

- Builds with both PyYAML 3.13 and 5.1 (#49).


1.8.0 (2019-03-09)
------------------

- Exit code 1 is returned only in conjunction with `--show-whitelisted` (#45).
- Fix bug in the processing of the 'until' whitelist field (#43).


1.7.1 (2018-07-23)
------------------

- Improve error messages when TOML files contain syntax errors.
- Fix install requirements so that they match upstream nixpkgs
  (NixOS/nixpkgs#43999).


1.7 (2018-07-20)
----------------

- Selective CVE reporting: Only those CVEs are reported for which no whitelist
  entry exists (#41).
- Consider all applicable whitelist entries for a given package (pkg-version,
  pkg, "*") (#42).
- Refine TOML section header check.


1.6.3 (2018-05-02)
------------------

- *Really* fix FC-101294. Now for whitelists containing more than one line :)
- Fail on spaces between package and version in whitelist headers.


1.6.2 (2018-05-02)
------------------

- Sort CVEs in JSON output.
- Bugfix: fail clearly if section headers are not quoted (FC-101294).


1.6.1 (2018-04-20)
------------------

- Parse derivation files with `__structuredAttrs = true` (#37).


1.6.0 (2018-04-19)
------------------

- Completely reworked whitelisting subsystem. Whitelists can now be written as
  TOML files and support a more expressive range of options including expiry
  datedates. The old YAML syntax is still supported (#36).
- Ignore case when guessing CVE identifiers from patch file names (thanks to
  @adisbladis).
- Add man pages (#29).


1.4.0 (2017-11-27)
------------------

- Guesses applied CVE patches out of the `patches` derivation envVar (see
  nixpkgs FC-15660).


1.3.4 (2017-10-29)
------------------

- Add '--no-requisites' flag which stops vulnix from determining the transitive
  closure of derivations passed on the command line.
- Provide structured JSON output with `--json`.
- Remove whitelist from README as it is quite buggy right now.


1.3.3 (2017-10-16)
------------------

- Fix return code bug (FC-28741).
- Fix partial whitelisting of products where several vulnerable versions are
  present on the system at the same time (#24).
- Improve error reporting for incorrectly formed whitelist rules.


1.3.2 (2017-10-06)
------------------

- Minor: fix packaging issues.


1.3.1 (2017-10-06)
------------------

- Security: Fix arbitrary code execution bug during derivation evaluation.


1.3.0 (2017-09-18)
------------------

- `.drv` files may be specified directly on the command line.
- Updated PyPI dependencies.
- Document system requirements (#12).
- Don't leave large files in /tmp around.
- Remove duplicate CVEs in output (#25).
- Fix bug with reporting less than 3 vulnerabilities (#28).


1.2.2 (2017-01-28)
------------------

- Packaging improvements: pin versions in setup.py, include NVDCVE test data in
  sdist.
- Reduce NVDCVE fixture size. This cuts tests run time by more than 50%.


1.2.1 (2017-01-27)
------------------

- Skip `/nix/var/nix/gcroots/booted-system` during system check.
- Make output a bit easier to read by removing visual clutter.


1.2 (2016-12-22)
----------------

- Improve CPU and memory usage: refactored the way we fetch, parse, store and
  process data. We now leverage ZODB as the storage for parsed data that is
  efficient to look up.

  On our test systems this caused memory usage to drop from > 1GiB to ~70MiB
  and a pure evaluation of existing data to around 7-10 seconds.

  This change requires a re-retrieval of all historic sources.

- Improve unit test coverage with at least a smoke test for our new fetching
  procedure.

1.1.5 (2016-10-13)
------------------

- Keep a reverse index: product name -> vulnerabilities to speed up scan process.
- Mark 'in progress' vulnerabilities with an asterisk
- The '-w' switch accepts URLs, too
- vulnix no longer scans /var/nix/var/gcroots/booted-system
- only cached files are saved (archives are to be deleted)
- added travis build: runs periodically against nixpkgs/master and updates
  requirements*.nix files in case of success


1.1.4 (2016-08-25)
------------------

- Add `src` to PYTHONPATH so that tests run also on older NixOS versions
  (tested on 15.09).
- Correct URL, add metadata.
- Add nix to propagatedBuildInputs, as vulnix calls `nix-store` at runtime.


1.1.3 (2016-08-16)
------------------

- Pin the Python version to 3.4 (Nix only)


1.1.2 (2016-08-15)
------------------

- Add Nix expressions (Nix/NixOS) to MANIFEST.in


1.1.1 (2016-08-12)
------------------

- Add VERSION to MANIFEST.in


1.1 (2016-08-11)
----------------

- Scans the whole system (NixOS only), the current user environment, or a
  project-specific path (e.g., ./result). #1

- Allow to specify site-specific whitelists in addition to the builtin default
  whitelist. #4

- Fully repeatable install using default.nix. Thanks to Rok Garbas. #4

- Cache pre-parsed NVD files for improved scanning speed. #2

- Support multiple whitelists (repeat -w option). #3

- Cache NVD files in `~/.cache/vulnix`. #7

- Document whitelist file format. #10

- Fix Nix build on macOS. #11