vulnix 1.6.3

Scans a Nix store for derivations that are affected by vulnerabilities.

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:

Found 5 advisories

========================================================================
libxslt-1.1.29

CVEs:
        https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2017-5029

========================================================================
pcre-8.40

CVEs:
        https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2017-7245
        https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2017-7244
        [...]

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.

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 1.11.

• 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";
  })
];

Building vulnix

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

python3.6 -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

Changes

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