Have you ever been in an environment where direct network access is blocked, but cloud services like Azure Blob Storage are still reachable? What if I told you that you could tunnel your internet traffic through those blob storage endpoints? That’s exactly what ProxyBlob does. In this post, I’ll walk you through what ProxyBlob is, how it works, how to set it up, and how you can use it to build a SOCKS proxy in restricted environments using Azure Blob Storage. Prefer watching instead of reading? Here’s a quick video guide Prefer watching instead of reading? Here’s a quick video guide Prefer watching instead of reading? Here’s a quick video guide Prefer watching instead of reading? Here’s a quick video guide https://youtu.be/Yf4-S5kpm_0?embedable=true https://youtu.be/Yf4-S5kpm_0?embedable=true What Is ProxyBlob? ProxyBlob is an open-source tool developed by Quarkslab that lets you create a SOCKS5 proxy tunnel through Azure Blob Storage. It helps your apps connect to the internet indirectly, by routing your traffic through Azure’s blob storage service.
It’s ideal for situations where *.blob.core.windows.net is allowed, but other outbound traffic is blocked (e.g., in corporate or monitored networks). It helps your apps connect to the internet indirectly, by routing your traffic through Azure’s blob storage service. It’s ideal for situations where *.blob.core.windows.net is allowed, but other outbound traffic is blocked (e.g., in corporate or monitored networks). Components of ProxyBlob ProxyBlob has two main parts: Proxy Server – This runs on your machine and offers a SOCKS5 proxy interface.
Agent – This runs inside the restricted target network and communicates with the proxy using Azure Blob Storage. Proxy Server – This runs on your machine and offers a SOCKS5 proxy interface. Agent – This runs inside the restricted target network and communicates with the proxy using Azure Blob Storage. These two talk to each other by sending and receiving data via blobs. Features of ProxyBlob SOCKS5 protocol support (TCP + UDP)
Works entirely via Azure Blob Storage
CLI with interactive commands
Can manage multiple agents
Easy to test locally using Azurite (Azure emulator) SOCKS5 protocol support (TCP + UDP) Works entirely via Azure Blob Storage CLI with interactive commands Can manage multiple agents Easy to test locally using Azurite (Azure emulator) Prerequisites Before diving into setup, make sure you have: Go 1.23+ installed
An Azure account
Access to create Azure Storage Accounts
Optionally, Docker or VS Code if testing with Azurite Go 1.23+ installed An Azure account Access to create Azure Storage Accounts Optionally, Docker or VS Code if testing with Azurite Setting Up ProxyBlob Let’s break this into simple steps: Create an Azure Storage Account You need a Premium Block Blob Storage Account. Here’s how you can do it via the Azure Portal: Go to https://portal.azure.com
Search for “Storage accounts” and click ”+ Create”
Fill in the form:

Name: your-storage-name
Region: Close to you
Performance: Premium
Redundancy: LRS
Account kind: BlockBlobStorage Go to https://portal.azure.com https://portal.azure.com Search for “Storage accounts” and click ”+ Create” Fill in the form:

Name: your-storage-name
Region: Close to you
Performance: Premium
Redundancy: LRS
Account kind: BlockBlobStorage Name: your-storage-name
Region: Close to you
Performance: Premium
Redundancy: LRS
Account kind: BlockBlobStorage Name: your-storage-name Region: Close to you Performance: Premium Redundancy: LRS Account kind: BlockBlobStorage Once created, go to Security + networking > Access keys to get your storage credentials. Or use the Azure CLI: az login
az group create --name proxyblob-rg --location "Central US"
az storage account create \
  --name myproxyblob \
  --resource-group proxyblob-rg \
  --location "Central US" \
  --sku "Premium_LRS" \
  --kind BlockBlobStorage
az storage account keys list --account-name myproxyblob --output table az login
az group create --name proxyblob-rg --location "Central US"
az storage account create \
  --name myproxyblob \
  --resource-group proxyblob-rg \
  --location "Central US" \
  --sku "Premium_LRS" \
  --kind BlockBlobStorage
az storage account keys list --account-name myproxyblob --output table Local Testing with Azurite If you just want to test locally: With VS Code extension: Install the Azurite extension
Start the Blob Service Install the Azurite extension Start the Blob Service With Docker: docker pull mcr.microsoft.com/azure-storage/azurite
docker run -p 10000:10000 mcr.microsoft.com/azure-storage/azurite docker pull mcr.microsoft.com/azure-storage/azurite
docker run -p 10000:10000 mcr.microsoft.com/azure-storage/azurite Default creds: Account: devstoreaccount1
Key: (Long key provided in README) Account: devstoreaccount1 Key: (Long key provided in README) Clone and Build ProxyBlob git clone https://github.com/quarkslab/proxyblob
cd proxyblob
make git clone https://github.com/quarkslab/proxyblob
cd proxyblob
make This builds two binaries: proxy – for your local machine
agent – for the restricted network proxy – for your local machine agent – for the restricted network Configuration Create a config file like this: {
  "storage_url": "http://localhost:10000/",  // remove if using real Azure
  "storage_account_name": "your-storage-name",
  "storage_account_key": "your-key"
} {
  "storage_url": "http://localhost:10000/",  // remove if using real Azure
  "storage_account_name": "your-storage-name",
  "storage_account_key": "your-key"
} Save it as config.json or my-config.json. Running ProxyBlob Start the Proxy Server ./proxy -c my-config.json ./proxy -c my-config.json This launches an interactive CLI. Key commands: create – generates a new agent container and a connection string
list – shows agent status
select – selects agent
start – starts the proxy listener (default port: 1080) create – generates a new agent container and a connection string list – shows agent status select – selects agent start – starts the proxy listener (default port: 1080) Example: proxyblob » create
proxyblob » list
proxyblob » select <container-id>
proxyblob » start proxyblob » create
proxyblob » list
proxyblob » select <container-id>
proxyblob » start Start the Agent You have two ways to pass the connection string: Via CLI: ./agent -c <generated-connection-string> ./agent -c <generated-connection-string> Or embed at build time: make agent TOKEN=<generated-connection-string>
./agent make agent TOKEN=<generated-connection-string>
./agent How It Works (Architecture) Here’s a simplified explanation of the workflow: Proxy writes requests as blobs into Azure storage
Agent polls the blobs, reads the request, and processes it
Agent writes back the response into a separate blob
Proxy reads the response and forwards it to the client app Proxy writes requests as blobs into Azure storage Agent polls the blobs, reads the request, and processes it Agent writes back the response into a separate blob Proxy reads the response and forwards it to the client app This creates a loop that emulates a direct SOCKS5 tunnel — but completely through blob storage. You can now use tools like proxychains: proxychains curl http://example.com
proxychains xfreerdp /v:myhost /u:user proxychains curl http://example.com
proxychains xfreerdp /v:myhost /u:user Troubleshooting Tips Check the exit code: echo $? echo $? Common Fixes: Check Azure credentials
Verify storage account accessibility
Look for firewall issues
Ensure correct connection string Check Azure credentials Verify storage account accessibility Look for firewall issues Ensure correct connection string What’s Coming Next? According to the README, future improvements may include: Support for the BIND SOCKS command
Better error handling
Speed optimizations Support for the BIND SOCKS command Better error handling Speed optimizations Final Thoughts ProxyBlob is a powerful example of protocol tunneling using cloud services. It’s especially useful for red teamers, pentesters, and defenders to understand the potential abuse of cloud storage services. If you’re serious about network security, covert channels, or cloud abuse scenarios, I highly recommend experimenting with ProxyBlob — just make sure to use it ethically and responsibly.

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Set Up a SOCKS Proxy via Azure Blob Storage in Restricted Networks

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