gokart : Static Analysis Tool For Securing Go code

GoKart is a static analysis tool for Go that finds vulnerabilities using the SSA (single static assignment) form of Go source code. It is capable of tracing the source of variables and function arguments to determine whether input sources are safe, which reduces the number of false positives compared to other Go security scanners. For instance, a SQL query that is concatenated with a variable might traditionally be flagged as SQL injection; however, GoKart can figure out if the variable is actually a constant or constant equivalent, in which case there is no vulnerability.

GoKart also helps to power Chariot, Praetorian’s security platform that helps you find, manage, and fix vulnerabilities in your source code and cloud environments. Chariot makes it simple to run automated, continuous GoKart scans on your source code. If you want to try GoKart, you can set up a free Chariot account in minutes by clicking here.

Why We Built GoKart

Static analysis is a powerful technique for finding vulnerabilities in source code. However, the approach has suffered from being noisy – that is, many static analysis tools find quite a few “vulnerabilities” that are not actually real. This has led to developer friction as users get tired of the tools “crying wolf” one time too many.

The motivation for GoKart was to address this: could we create a scanner with significantly lower false positive rates than existing tools? Based on our experimentation the answer is yes. By leveraging source-to-sink tracing and SSA, GoKart is capable of tracking variable taint between variable assignments, significantly improving the accuracy of findings. Our focus is on usability: pragmatically, that means we have optimized our approaches to reduce false alarms.

Install

You can install GoKart locally by using any one of the options listed below.

Install with go install

$ go install github.com/praetorian-inc/gokart@latest

Install a release binary

• Download the binary for your OS from the releases page.
• (OPTIONAL) Download the checksums.txt file to verify the integrity of the archive

Getting Started – Scanning an Example App

You can follow the steps below to run GoKart on Go Test Bench, an intentionally vulnerable Go application from the Contrast Security team

Clone sample vulnerable application
git clone https://github.com/Contrast-Security-OSS/go-test-bench.git
gokart scan go-test-bench/

Output should show some identified vulnerabilities, each with a Vulnerable Function and Source of User Input identified.

To test some additional GoKart features, you can scan with the CLI flags suggested below.

Use verbose flag to show full traces of these vulnerabilities
gokart scan go-test-bench/ -v
Use globalsTainted flag to ignore whitelisted Sources
may increase false positive results
gokart scan go-test-bench/ -v -g
Use debug flag to display internal analysis information
which is useful for development and debugging
gokart scan go-test-bench/ -d
Output results in sarif format
gokart scan go-test-bench/ -s
Output results to file
gokart scan go-test-bench/ -o gokart-go-test-bench.txt
Output scarif results to file
gokart scan go-test-bench/ -o gokart-go-test-bench.txt -s
Scan remote public repository
Repository will be cloned locally, scanned and deleted afterwards
gokart scan -r https://github.com/ShiftLeftSecurity/shiftleft-go-demo -v
Specify the remote branch to scan
gokart scan -r https://github.com/ShiftLeftSecurity/shiftleft-go-demo -b actions_fix
Scan remote private repository via ssh
gokart scan -r git@github.com:Contrast-Security-OSS/go-test-bench.git
Scan remote private repository and optionally specify a key for ssh authentication
gokart scan -r git@github.com:Contrast-Security-OSS/go-test-bench.git -k /home/gokart/.ssh/github_rsa_key
Use remote scan and output flags together for seamless security reviews
gokart scan -r https://github.com/ShiftLeftSecurity/shiftleft-go-demo -o gokart-shiftleft-go-demo.txt -v
Use remote scan, output and sarif flags for frictionless integration into CI/CD
gokart scan -r https://github.com/ShiftLeftSecurity/shiftleft-go-demo -o gokart-shiftleft-go-demo.txt -s

To test out the extensibility of GoKart, you can modify the configuration file that GoKart uses to introduce a new vulnerable sink into analysis. There is a Test Sink analyzer defined in the included default config file at util/analyzers.yml. Modify util/analyzers.yml to remove the comments on the Test Sink analyzer and then direct GoKart to use the modified config file with the -i flag.

Scan using modified analyzers.yml file and output full traces
gokart scan go-test-bench/ -v -i /util/analyzers.yml

Output should now contain additional vulnerabilities, including new “Test Sink reachable by user input” vulnerabilities.