gosec - Golang Security Checker

Inspects source code for security problems by scanning the Go AST.

License

Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance with the License. You may obtain a copy of the License here.

Project status

Install

CI Installation

# binary will be $(go env GOPATH)/bin/gosec
curl -sfL https://raw.githubusercontent.com/securego/gosec/master/install.sh | sh -s -- -b $(go env GOPATH)/bin vX.Y.Z

# or install it into ./bin/
curl -sfL https://raw.githubusercontent.com/securego/gosec/master/install.sh | sh -s vX.Y.Z

# In alpine linux (as it does not come with curl by default)
wget -O - -q https://raw.githubusercontent.com/securego/gosec/master/install.sh | sh -s vX.Y.Z

# If you want to use the checksums provided on the "Releases" page
# then you will have to download a tar.gz file for your operating system instead of a binary file
wget https://github.com/securego/gosec/releases/download/vX.Y.Z/gosec_vX.Y.Z_OS.tar.gz

# The file will be in the current folder where you run the command
# and you can check the checksum like this
echo "<check sum from the check sum file>  gosec_vX.Y.Z_OS.tar.gz" | sha256sum -c -

gosec --help

GitHub Action

You can run gosec as a GitHub action as follows:

name: Run Gosec
on:
  push:
    branches:
      - master
  pull_request:
    branches:
      - master
jobs:
  tests:
    runs-on: ubuntu-latest
    env:
      GO111MODULE: on
    steps:
      - name: Checkout Source
        uses: actions/checkout@v2
      - name: Run Gosec Security Scanner
        uses: securego/gosec@master
        with:
          args: ./...

Integrating with code scanning

You can integrate third-party code analysis tools with GitHub code scanning by uploading data as SARIF files.

The workflow shows an example of running the gosec as a step in a GitHub action workflow which outputs the results.sarif file. The workflow then uploads the results.sarif file to GitHub using the upload-sarif action.

name: "Security Scan"

# Run workflow each time code is pushed to your repository and on a schedule.
# The scheduled workflow runs every at 00:00 on Sunday UTC time.
on:
  push:
  schedule:
  - cron: '0 0 * * 0'

jobs:
  tests:
    runs-on: ubuntu-latest
    env:
      GO111MODULE: on
    steps:
      - name: Checkout Source
        uses: actions/checkout@v2
      - name: Run Gosec Security Scanner
        uses: securego/gosec@master
        with:
          # we let the report trigger content trigger a failure using the GitHub Security features.
          args: '-no-fail -fmt sarif -out results.sarif ./...'
      - name: Upload SARIF file
        uses: github/codeql-action/upload-sarif@v1
        with:
          # Path to SARIF file relative to the root of the repository
          sarif_file: results.sarif

Local Installation

Go 1.16+

go install github.com/securego/gosec/v2/cmd/gosec@latest

Go version < 1.16

go get -u github.com/securego/gosec/v2/cmd/gosec

Usage

Gosec can be configured to only run a subset of rules, to exclude certain file paths, and produce reports in different formats. By default all rules will be run against the supplied input files. To recursively scan from the current directory you can supply ./... as the input argument.

Available rules

• G101: Look for hard coded credentials
• G102: Bind to all interfaces
• G103: Audit the use of unsafe block
• G104: Audit errors not checked
• G106: Audit the use of ssh.InsecureIgnoreHostKey
• G107: Url provided to HTTP request as taint input
• G108: Profiling endpoint automatically exposed on /debug/pprof
• G109: Potential Integer overflow made by strconv.Atoi result conversion to int16/32
• G110: Potential DoS vulnerability via decompression bomb
• G111: Potential directory traversal
• G112: Potential slowloris attack
• G113: Usage of Rat.SetString in math/big with an overflow (CVE-2022-23772)
• G114: Use of net/http serve function that has no support for setting timeouts
• G201: SQL query construction using format string
• G202: SQL query construction using string concatenation
• G203: Use of unescaped data in HTML templates
• G204: Audit use of command execution
• G301: Poor file permissions used when creating a directory
• G302: Poor file permissions used with chmod
• G303: Creating tempfile using a predictable path
• G304: File path provided as taint input
• G305: File traversal when extracting zip/tar archive
• G306: Poor file permissions used when writing to a new file
• G401: Detect the usage of DES, RC4, MD5 or SHA1
• G402: Look for bad TLS connection settings
• G403: Ensure minimum RSA key length of 2048 bits
• G404: Insecure random number source (rand)
• G501: Import blocklist: crypto/md5
• G502: Import blocklist: crypto/des
• G503: Import blocklist: crypto/rc4
• G504: Import blocklist: net/http/cgi
• G505: Import blocklist: crypto/sha1
• G601: Implicit memory aliasing of items from a range statement

Retired rules

• G105: Audit the use of math/big.Int.Exp - CVE is fixed
• G307: Deferring a method which returns an error - causing more inconvenience than fixing a security issue, despite the details from this blog post

Selecting rules

By default, gosec will run all rules against the supplied file paths. It is however possible to select a subset of rules to run via the -include= flag, or to specify a set of rules to explicitly exclude using the -exclude= flag.

# Run a specific set of rules
$ gosec -include=G101,G203,G401 ./...

# Run everything except for rule G303
$ gosec -exclude=G303 ./...

CWE Mapping

Every issue detected by gosec is mapped to a CWE (Common Weakness Enumeration) which describes in more generic terms the vulnerability. The exact mapping can be found here.

Configuration

A number of global settings can be provided in a configuration file as follows:

{
    "global": {
        "nosec": "enabled",
        "audit": "enabled"
    }
}

• nosec: this setting will overwrite all #nosec directives defined throughout the code base
• audit: runs in audit mode which enables addition checks that for normal code analysis might be too nosy

# Run with a global configuration file
$ gosec -conf config.json .

Also some rules accept configuration. For instance on rule G104, it is possible to define packages along with a list of functions which will be skipped when auditing the not checked errors:

{
    "G104": {
        "ioutil": ["WriteFile"]
    }
}

You can also configure the hard-coded credentials rule G101 with additional patterns, or adjust the entropy threshold:

{
    "G101": {
        "pattern": "(?i)passwd|pass|password|pwd|secret|private_key|token",
         "ignore_entropy": false,
         "entropy_threshold": "80.0",
         "per_char_threshold": "3.0",
         "truncate": "32"
    }
}

Dependencies

gosec will fetch automatically the dependencies of the code which is being analyzed when go module is turned on (e.g.GO111MODULE=on). If this is not the case, the dependencies need to be explicitly downloaded by running the go get -d command before the scan.

Excluding test files and folders

gosec will ignore test files across all packages and any dependencies in your vendor directory.

The scanning of test files can be enabled with the following flag:

gosec -tests ./...

Also additional folders can be excluded as follows:

 gosec -exclude-dir=rules -exclude-dir=cmd ./...

Excluding generated files

gosec can ignore generated go files with default generated code comment.

// Code generated by some generator DO NOT EDIT.

gosec -exclude-generated ./...

Annotating code

As with all automated detection tools, there will be cases of false positives. In cases where gosec reports a failure that has been manually verified as being safe, it is possible to annotate the code with a comment that starts with #nosec. The #nosec comment should have the format #nosec [RuleList] [-- Justification].

The annotation causes gosec to stop processing any further nodes within the AST so can apply to a whole block or more granularly to a single expression.

import "md5" //#nosec


func main(){

    /* #nosec */
    if x > y {
        h := md5.New() // this will also be ignored
    }

}

When a specific false positive has been identified and verified as safe, you may wish to suppress only that single rule (or a specific set of rules) within a section of code, while continuing to scan for other problems. To do this, you can list the rule(s) to be suppressed within the #nosec annotation, e.g: /* #nosec G401 */ or //#nosec G201 G202 G203

You could put the description or justification text for the annotation. The justification should be after the rule(s) to suppress and start with two or more dashes, e.g: //#nosec G101 G102 -- This is a false positive

In some cases you may also want to revisit places where #nosec annotations have been used. To run the scanner and ignore any #nosec annotations you can do the following:

gosec -nosec=true ./...

Tracking suppressions

As described above, we could suppress violations externally (using -include/ -exclude) or inline (using #nosec annotations) in gosec. This suppression inflammation can be used to generate corresponding signals for auditing purposes.

We could track suppressions by the -track-suppressions flag as follows:

gosec -track-suppressions -exclude=G101 -fmt=sarif -out=results.sarif ./...

• For external suppressions, gosec records suppression info where kind is external and justification is a certain sentence "Globally suppressed".
• For inline suppressions, gosec records suppression info where kind is inSource and justification is the text after two or more dashes in the comment.

Note: Only SARIF and JSON formats support tracking suppressions.

Build tags

gosec is able to pass your Go build tags to the analyzer. They can be provided as a comma separated list as follows:

gosec -tags debug,ignore ./...

Output formats

gosec currently supports text, json, yaml, csv, sonarqube, JUnit XML, html and golint output formats. By default results will be reported to stdout, but can also be written to an output file. The output format is controlled by the -fmt flag, and the output file is controlled by the -out flag as follows:

# Write output in json format to results.json
$ gosec -fmt=json -out=results.json *.go

Results will be reported to stdout as well as to the provided output file by -stdout flag. The -verbose flag overrides the output format when stdout the results while saving them in the output file

# Write output in json format to results.json as well as stdout
$ gosec -fmt=json -out=results.json -stdout *.go

# Overrides the output format to 'text' when stdout the results, while writing it to results.json
$ gosec -fmt=json -out=results.json -stdout -verbose=text *.go

Note: gosec generates the generic issue import format for SonarQube, and a report has to be imported into SonarQube using sonar.externalIssuesReportPaths=path/to/gosec-report.json.

Development

Build

You can build the binary with:

make

Note on Sarif Types Generation

Install the tool with :

go get -u github.com/a-h/generate/cmd/schema-generate

Then generate the types with :

schema-generate -i sarif-schema-2.1.0.json -o mypath/types.go

Most of the MarshallJSON/UnmarshalJSON are removed except the one for PropertyBag which is handy to inline the additional properties. The rest can be removed. The URI,ID, UUID, GUID were renamed so it fits the Golang convention defined here

Tests

You can run all unit tests using:

make test

Release

You can create a release by tagging the version as follows:

git tag v1.0.0 -m "Release version v1.0.0"
git push origin v1.0.0

The GitHub release workflow triggers immediately after the tag is pushed upstream. This flow will release the binaries using the goreleaser action and then it will build and publish the docker image into Docker Hub.

The released artifacts are signed using cosign. You can use the public key from cosign.pub file to verify the signature of docker image and binaries files.

The docker image signature can be verified with the following command:

cosign verify --key cosign.pub securego/gosec:<TAG>

The binary files signature can be verified with the following command:

cosign verify-blob --key cosign.pub --signature gosec_<VERSION>_darwin_amd64.tar.gz.sig  gosec_<VERSION>_darwin_amd64.tar.gz

Docker image

You can also build locally the docker image by using the command:

make image

You can run the gosec tool in a container against your local Go project. You only have to mount the project into a volume as follows:

docker run --rm -it -w /<PROJECT>/ -v <YOUR PROJECT PATH>/<PROJECT>:/<PROJECT> securego/gosec /<PROJECT>/...

Note: the current working directory needs to be set with -w option in order to get successfully resolved the dependencies from go module file

Generate TLS rule

The configuration of TLS rule can be generated from Mozilla's TLS ciphers recommendation.

First you need to install the generator tool:

go get github.com/securego/gosec/v2/cmd/tlsconfig/...

You can invoke now the go generate in the root of the project:

go generate ./...

This will generate the rules/tls_config.go file which will contain the current ciphers recommendation from Mozilla.

Who is using gosec?

This is a list with some of the gosec's users.

Sponsors

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