A source code analyzer built for surfacing features of interest and other characteristics to answer the question 'What's in the code?' quickly using static analysis with a json based rules engine. Ideal for scanning components before use or detecting feature level changes.
Under MIT License
By microsoft

security-tools security-scanner detection static-analysis software-characterization application-inspector


Microsoft Application Inspector is a software source code characterization tool that helps identify coding features of first or third party software components based on well-known library/API calls and is helpful in security and non-security use cases. It uses hundreds of rules and regex patterns to surface interesting characteristics of source code to aid in determining what the software is or what it does from what file operations it uses, encryption, shell operations, cloud API's, frameworks and more and has received industry attention as a new and valuable contribution to OSS on ZDNet, SecurityWeek, CSOOnline,, HelpNetSecurity, Twitter and more and was first featured on

Application Inspector is different from traditional static analysis tools in that it doesn't attempt to identify "good" or "bad" patterns; it simply reports what it finds against a set of over 400 rule patterns for feature detection including features that impact security such as the use of cryptography and more. This can be extremely helpful in reducing the time needed to determine what Open Source or other components do by examining the source directly rather than trusting to limited documentation or recommendations.

The tool supports scanning various programming languages including C, C++, C#, Java, JavaScript, HTML, Python, Objective-C, Go, Ruby, PowerShell and more and can scan projects with mixed language files. It supports generating results in HTML, JSON and text output formats with the default being an HTML report similar to the one shown here.

Be sure to see our complete project wiki page for additional information and help.

Quick Start
Obtain Application Inspector
.NET Tool (recommended)

See more in the wiki

Platform Dependent Binary

Run Application Inspector


Microsoft Application Inspector helps you in securing your applications from start to deployment.

Design Choices - Enables you to choose which components meet your needs with a smaller footprint of unnecessary or unknowns features for keeping your application attack surface smaller as well as help to verify expected ones i.e. industry standard crypto only.

Identifying Feature Deltas - Detects changes between component versions which can be critical for detecting injection of backdoors.

Automating Security Compliance Checks - Use to identify components with features that require additional security scrutiny, approval or SDL compliance as part of your build pipeline or create a repository of metadata regarding all of your enterprise application.


We have a strong default starting base of Rules for feature detection. But there are many feature identification patterns yet to be defined and we invite you to submit ideas on what you want to see or take a crack at defining a few. This is a chance to literally impact the open source ecosystem helping provide a tool that everyone can use. See the Rules section of the wiki for more.

Official Releases

Application Inspector is in GENERAL AUDIENCE release status. Your feedback is important to us. If you're interested in contributing, please review the

Application Inspector is availble as a command line tool or NuGet package and is supported on Windows, Linux, or MacOS.

Platform specific binaries of the ApplicationInspector CLI are available on our GitHub releases page.

The C# library is available on NuGet as Microsoft.CST.ApplicationInspector.Commands.

The .NET Global Tool is available on NuGet as Microsoft.CST.ApplicationInspector.CLI.

If you use the .NET Core version, you will need to have .NET Core 5.0 or later installed. See the or files for more.

CLI Usage Information


appinspector --help
ApplicationInspector.CLI 1.4.0+6bdef0356b
c Microsoft Corporation. All rights reserved.

analyze Inspect source directory/file/compressed file (.tgz|zip) against defined characteristics

tagdiff Compares unique tag values between two source paths

exporttags Export unique rule tags to view what code features may be detected

verifyrules Verify custom rules syntax is valid

packrules Combine multiple rule files into one file for ease in distribution

help Display more information on a specific command.

version Display version information.

Command Help

To get help for a specific command run appinspector <command> --help.

Analyze Command

The Analyze Command is the workhorse of Application Inspector.

Simple Default Analyze

This will produce an output.html of the analysis in the current directory using default arguments and rules.
appinspector analyze -s path/to/files

Excluding Files using Globs

This will create a json output named data.json of the analysis in the current directory, excluding all files in test and .git folders using the provided glob patterns.
appinspector analyze -s path/to/files -o data.json -f json -g **/tests/**,**/.git/**

Additional Usage Information


appinspector analyze --help
ApplicationInspector.CLI 1.4.0+6bdef0356b
c Microsoft Corporation. All rights reserved.

-s, --source-path Required. Source file or directory to inspect, comma separated

-r, --custom-rules-path Custom rules file or directory path

-i, --ignore-default-rules (Default: false) Exclude default rules bundled with application

-c, --confidence-filters (Default: high,medium) Output only matches with specified confidence , [high|medium|low]

-g, --exclusion-globs (Default: /bin/ /obj/ /.vs/ /.git/) Exclude source files that match glob patterns. Example: "/.git/,Tests". Use "none" to disable.

-f, --output-file-format (Default: html) Output format [html|json|text]

-e, --text-format (Default: Tag:%T,Rule:%N,Ruleid:%R,Confidence:%X,File:%F,Sourcetype:%t,Line:%L,Sample:%m) Match text format specifiers

--file-timeout (Default: 60000) If set, maximum amount of time in milliseconds to allow for processing each file.

--processing-timeout (Default: 0) If set, maximum amount of time in milliseconds to allow for processing overall.

--single-threaded Disables parallel processing.

--no-show-progress Disable progress information.

--context-lines Number of lines of context on each side to include in excerpt (up to a maximum of 100 * NumLines characters on each side). 0 to skip exerpt. -1 to not extract
samples or excerpts (implied by -t).

--scan-unknown-filetypes Scan files of unknown types.

-t, --tags-only Only get tags (no detailed match data).

-n, --no-file-metadata Don't collect metadata about each individual file.

-o, --output-file-path Output file path

-x, --console-verbosity (Default: medium) Console verbosity [high|medium|low|none]

-l, --log-file-path Log file path

-v, --log-file-level (Default: Error) Log file level [Debug|Info|Warn|Error|Trace|Fatal|Off]

--help Display this help screen.

--version Display version information.
For additional help on use of the console interface see CLI Usage.

For help using the NuGet package see NuGet Support

Build Instructions