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https://github.com/atc0005/safelinks
Go-based tooling to manipulate (e.g., normalize/decode) Microsoft Office 365 "Safe Links" URLs; NOT affiliated with or endorsed by Microsoft Corporation.
https://github.com/atc0005/safelinks
go golang safelink safelinks
Last synced: 1 day ago
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Go-based tooling to manipulate (e.g., normalize/decode) Microsoft Office 365 "Safe Links" URLs; NOT affiliated with or endorsed by Microsoft Corporation.
- Host: GitHub
- URL: https://github.com/atc0005/safelinks
- Owner: atc0005
- License: mit
- Created: 2022-12-08T11:09:32.000Z (about 2 years ago)
- Default Branch: master
- Last Pushed: 2025-01-07T08:45:49.000Z (about 1 month ago)
- Last Synced: 2025-01-11T03:18:18.326Z (about 1 month ago)
- Topics: go, golang, safelink, safelinks
- Language: Go
- Homepage:
- Size: 13.7 MB
- Stars: 0
- Watchers: 2
- Forks: 1
- Open Issues: 10
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
- Security: SECURITY.md
Awesome Lists containing this project
- awesome-golang-repositories - safelinks - based tooling to manipulate (e.g., normalize/decode) Microsoft Office 365 "Safe Links" URLs (Repositories)
README
# safelinks
Go-based tooling to manipulate (e.g., normalize/decode) Microsoft Office 365
"Safe Links" URLs.
[](https://github.com/atc0005/safelinks/releases/latest)
[](https://pkg.go.dev/github.com/atc0005/safelinks)
[](https://github.com/atc0005/safelinks)
[](https://github.com/atc0005/safelinks/actions/workflows/lint-and-build.yml)
[](https://github.com/atc0005/safelinks/actions/workflows/project-analysis.yml)
## Table of Contents
- [Project home](#project-home)
- [Overview](#overview)
- [Features](#features)
- [`usl` CLI tool](#usl-cli-tool)
- [`dsl` CLI tool](#dsl-cli-tool)
- [`dslg` GUI tool](#dslg-gui-tool)
- [`eslg` GUI tool](#eslg-gui-tool)
- [Changelog](#changelog)
- [Requirements](#requirements)
- [Building source code](#building-source-code)
- [Running](#running)
- [Installation](#installation)
- [From source](#from-source)
- [Using release binaries](#using-release-binaries)
- [Deployment](#deployment)
- [Configuration](#configuration)
- [Command-line arguments](#command-line-arguments)
- [`usl`](#usl)
- [Flags](#flags)
- [Positional Argument](#positional-argument)
- [Standard input (e.g., "piping")](#standard-input-eg-piping)
- [Without arguments or flags](#without-arguments-or-flags)
- [`dsl`](#dsl)
- [Flags](#flags-1)
- [Positional Argument](#positional-argument-1)
- [Standard input (e.g., "piping")](#standard-input-eg-piping-1)
- [Without arguments or flags](#without-arguments-or-flags-1)
- [`dslg`](#dslg)
- [`eslg`](#eslg)
- [Examples](#examples)
- [`usl` tool](#usl-tool)
- [Using url positional argument](#using-url-positional-argument)
- [Using url flag](#using-url-flag)
- [Using input prompt](#using-input-prompt)
- [Using standard input (e.g., "piping")](#using-standard-input-eg-piping)
- [Using filename flag](#using-filename-flag)
- [Verbose output](#verbose-output)
- [`dsl` tool](#dsl-tool)
- [Using url positional argument](#using-url-positional-argument-1)
- [Using url flag](#using-url-flag-1)
- [Using input prompt](#using-input-prompt-1)
- [Using standard input (e.g., "piping")](#using-standard-input-eg-piping-1)
- [Using filename flag](#using-filename-flag-1)
- [`dslg` tool](#dslg-tool)
- [`eslg` tool](#eslg-tool)
- [License](#license)
- [References](#references)
- [General](#general)
- [Observed safelinks.protection.outlook.com subdomains](#observed-safelinksprotectionoutlookcom-subdomains)
- [Alternative decoders](#alternative-decoders)
## Project home
See [our GitHub repo][repo-url] for the latest code, to file an issue or
submit improvements for review and potential inclusion into the project.
## Overview
This repo is intended to provide various tools used to manipulate (e.g.,
normalize/decode) Microsoft Office 365 "Safe Links" URLs.
| Tool Name | Overall Status | Description |
| --------- | -------------- | ------------------------------------------------------------------------- |
| `usl` | 🆗Beta | Small CLI tool for decoding a given Safe Links URL. |
| `dsl` | 💥Alpha | Small CLI tool for decoding Safe Links URLs within input text. |
| `dslg` | 💥Alpha | GUI tool for decoding Safe Links URLs within input text. |
| `eslg` | 💥Alpha | GUI tool for encoding normal URLs within input text for testing purposes. |
## Features
### `usl` CLI tool
Small CLI tool for decoding a given Safe Links URL.
- Specify single Safe Links URL
- [x] via positional argument
- [x] via flag
- [x] via interactive prompt
- Specify multiple bare Safe Links URLs (no surrounding text)
- [ ] via interactive prompt
- [x] via standard input ("piping")
- [x] via file (using flag)
- Optional verbose listing of query parameter values within a given Safe Links
URL.
### `dsl` CLI tool
Small CLI tool for decoding Safe Links URLs within surrounding input text.
- Specify single Safe Links URL
- [ ] via positional argument
- [ ] via flag
- [x] via interactive prompt
- Specify multiple Safe Links URLs (with surrounding text untouched)
- [x] via interactive prompt
- [x] via standard input ("piping")
- [ ] via file (using flag)
### `dslg` GUI tool
GUI tool for decoding Safe Links URLs within given input text.
- Specify single Safe Links URL
- Specify multiple Safe Links URLs (with surrounding text untouched)
### `eslg` GUI tool
GUI tool for generating test data.
## Changelog
See the [`CHANGELOG.md`](CHANGELOG.md) file for the changes associated with
each release of this application. Changes that have been merged to `master`,
but not yet an official release may also be noted in the file under the
`Unreleased` section. A helpful link to the Git commit history since the last
official release is also provided for further review.
## Requirements
The following is a loose guideline. Other combinations of Go and operating
systems for building and running tools from this repo may work, but have not
been tested.
### Building source code
- Go
- see this project's `go.mod` file for *preferred* version
- this project tests against [officially supported Go
releases][go-supported-releases]
- the most recent stable release (aka, "stable")
- the prior, but still supported release (aka, "oldstable")
- GCC
- if building with custom options (as the provided `Makefile` does)
- mingw-w64
- if building GUI app(s) for Windows
- used to perform CGO-enabled builds of Fyne (GUI) applications
- `make`
- if using the provided `Makefile`
- Fyle toolkit OS dependencies
- see for OS-specific packages
> [!TIP]
> Use `make docker-release-build` or `podman-release-build` Makefile recipes to generate/use build containers compatible with this project.
### Running
The CLI apps are broadly compatible but have been tested against:
- Microsoft Windows 10
- Ubuntu 20.04
The GUI app(s) have been tested against:
- Microsoft Windows 10
- Microsoft Windows 11
- Ubuntu 20.04
- `libgl1` package was needed
> [!NOTE]
> The build image used by this project has an inherited dependency on the official upstream Go Docker image
and shares that image's minimum glibc version requirement.
As of this writing, a glibc release of version 2.31 or newer is required to
match the Debian 11 base image used by current Go Docker images. Ubuntu 20.04
has glibc 2.31 and meets this requirement. Older distro versions may not meet
this requirement and will require building from source.
> [!IMPORTANT]
> When the upstream Go Docker image swaps out the minimum Debian base image OS (currently Debian 11) this may also mean dropping support for some Linux distros.
## Installation
### From source
> [!TIP]
> Use `docker-release-build` or `podman-release-build` Makefile recipes to use build containers compatible with this project.
1. [Download][go-docs-download] Go
1. [Install][go-docs-install] Go
1. Clone the repo
1. `cd /tmp`
1. `git clone https://github.com/atc0005/safelinks`
1. `cd safelinks`
1. Install dependencies (optional)
- for Ubuntu Linux
- if building for the current architecture
- `sudo apt-get install make gcc xz-utils libgl1-mesa-dev xorg-dev`
- if building x86 binaries on x64 OS
- `sudo dpkg --add-architecture i386`
- `sudo dpkg --configure -a`
- `sudo apt-get update`
- `sudo apt-get install make bsdmainutils gcc gcc-multilib
gcc-mingw-w64 xz-utils libgl1-mesa-dev xorg-dev`
- `sudo apt-get install libxinerama-dev:i386 libgl1-mesa-dev:i386
libxrandr-dev:i386 libxxf86vm-dev:i386 libxi-dev:i386
libxcursor-dev:i386`
- for CentOS Linux
1. `sudo yum install make gcc libXcursor-devel libXrandr-devel
mesa-libGL-devel libXi-devel libXinerama-devel libXxf86vm-devel`
1. Build
- for the detected current operating system and architecture, explicitly
using bundled dependencies in top-level `vendor` folder
- most likely this is what you want (if building manually)
- `go build -mod=vendor ./cmd/usl/`
- `go build -mod=vendor ./cmd/dsl/`
- `go build -mod=vendor ./cmd/dslg/`
- `go build -mod=vendor ./cmd/eslg/`
- manually, explicitly specifying target OS and architecture
- `GOOS=linux GOARCH=amd64 go build -mod=vendor ./cmd/usl/`
- substitute `GOARCH=amd64` with the appropriate architecture if using
different hardware (e.g., `GOARCH=arm64` or `GOARCH=386`)
- substitute `GOOS=linux` with the appropriate OS if using a different
platform (e.g., `GOOS=windows`)
- `GOOS=linux GOARCH=amd64 go build -mod=vendor ./cmd/dsl/`
- `GOOS=linux GOARCH=amd64 go build -mod=vendor ./cmd/dslg/`
- `GOOS=linux GOARCH=amd64 go build -mod=vendor ./cmd/eslg/`
- using Makefile `all` recipe
- `make all`
- generates x86 and x64 binaries
- using Makefile `release-build` recipe
- `make release-build`
- generates the same release assets as provided by this project's
releases
1. Locate generated binaries
- if using `Makefile`
- look in `/tmp/safelinks/release_assets/usl/`
- look in `/tmp/safelinks/release_assets/dsl/`
- look in `/tmp/safelinks/release_assets/dslg/`
- look in `/tmp/safelinks/release_assets/eslg/`
- if using `go build`
- look in `/tmp/safelinks/`
1. Copy the applicable binaries to whatever systems needs to run them so that
they can be deployed
> [!NOTE]
> Depending on which `Makefile` recipe you use the generated binary may be compressed and have an `xz` extension. If so, you should decompress the binary first before deploying it (e.g., `xz -d usl-linux-amd64.xz`).
### Using release binaries
1. Download the [latest release][releases-url] binaries
1. Decompress binaries
- e.g., `xz -d usl-linux-amd64.xz`
- 7-Zip also works well for this on Windows systems (e.g., for systems
without Git for Windows or WSL)
1. Copy the applicable binaries to whatever systems needs to run them so that
they can be deployed
**NOTE**:
DEB and RPM packages are provided as an alternative to manually deploying
binaries.
### Deployment
1. Place `usl` in a location where it can be easily accessed
1. Place `dsl` in a location where it can be easily accessed
1. Place `dslg` in a location where it can be easily accessed
1. Place `eslg` in a location where it can be easily accessed
> [!NOTE]
> The `libgl1` package is needed on target Ubuntu systems for the `dslg` and `eslg` apps.
## Configuration
### Command-line arguments
- Use the `-h` or `--help` flag to display current usage information.
- Flags marked as **`required`** must be set via CLI flag.
- Flags *not* marked as required are for settings where a useful default is
already defined, but may be overridden if desired.
> [!NOTE]
> 🛠️ The `dsl` tool does not support CLI arguments but may do so in the
> future.
#### `usl`
##### Flags
| Flag | Required | Default | Repeat | Possible | Description |
| ---------------- | -------- | ------- | ------ | -------------------- | ----------------------------------------------------------------------------- |
| `h`, `help` | No | `false` | No | `h`, `help` | Show Help text along with the list of supported flags. |
| `version` | No | `false` | No | `version` | Whether to display application version and then immediately exit application. |
| `v`, `verbose` | No | `false` | No | `v`, `verbose` | Display additional information about a given Safe Links URL. |
| `u`, `url` | *maybe* | | No | `u`, `url` | Safe Links URL to decode |
| `f`, `inputfile` | *maybe* | | No | *valid path to file* | Path to file containing Safe Links URLs to decode |
NOTE: If an input `url` is not specified (e.g., via flag, positional argument
or standard input) a prompt is provided to enter a Safe Links URL.
##### Positional Argument
A URL pattern is accepted as a single positional argument in place of the `u`
or `url` flag. It is recommended that you quote the URL pattern to help
prevent some of the characters from being interpreted as shell commands (e.g.,
`&` as an attempt to background a command).
##### Standard input (e.g., "piping")
One or more URL patterns can be provided by piping them to the `usl` tool.
An attempt is made to decode all input URLs (no early exit). Successful
decoding results are emitted to `stdout` with decoding failures emitted to
`stderr`. This allows for splitting success results and error output across
different files (e.g., for later review).
##### Without arguments or flags
The `usl` tool can also be called without any input (e.g., flags, positional
argument, standard input). In this scenario it will prompt you to insert/paste
the URL pattern (quoted or otherwise).
#### `dsl`
> [!IMPORTANT]
> This tool is in early development and behavior is subject to change.
##### Flags
> [!NOTE]
> 🛠️ This feature is not implemented but may be added in the future.
##### Positional Argument
> [!NOTE]
> 🛠️ This feature is not implemented but may be added in the future.
##### Standard input (e.g., "piping")
Text with interspersed URLs (separated by whitespace) can be provided for
decoding by piping it to the `dsl` tool. Output is sent to `stdout`.
Each matched Safe Links URL is replaced with a decoded version leaving
surrounding text as-is.
##### Without arguments or flags
The `dsl` tool can also be called without any input. In this scenario it will
prompt you to insert/paste content for decoding.
If no input is provided for a the listed amount of time the `dsl` tool will
timeout and exit.
#### `dslg`
No command-line arguments are currently supported.
#### `eslg`
No command-line arguments are currently supported.
## Examples
### `usl` tool
Though probably not required for all terminals, we quote the Safe Links URL to
prevent unintended interpretation of characters in the URL.
#### Using url positional argument
```console
$ usl 'SafeLinksURLHere'
https://go.dev/dl/
```
#### Using url flag
```console
$ usl --url 'SafeLinksURLHere'
https://go.dev/dl/
```
#### Using input prompt
In this example we just press enter so that we will be prompted for the input
URL pattern.
```console
$ usl
Enter URL: SafeLinksURLHere
https://go.dev/dl/
```
#### Using standard input (e.g., "piping")
```console
$ cat file.with.links | usl
https://go.dev/dl/
http://example.com
http://example.net
```
```console
$ echo 'SafeLinksURLHere' | usl
https://go.dev/dl/
```
#### Using filename flag
```console
$ usl --filename file.with.links
https://go.dev/dl/
http://example.com
http://example.net
```
#### Verbose output
```console
$ usl --verbose --url 'SafeLinksURLHere'
Expanded values from the given link:
data : PLACEHOLDER
host : nam99.safelinks.protection.outlook.com
reserved : 0
sdata : PLACEHOLDER
url : https://go.dev/dl/
```
### `dsl` tool
#### Using url positional argument
> [!NOTE]
> 🛠️ This feature is not implemented but may be added in the future.
#### Using url flag
> [!NOTE]
> 🛠️ This feature is not implemented but may be added in the future.
#### Using input prompt
In this example we just press enter so that we will be prompted for the input
URL pattern.
```console
$ dsl
Enter single or multi-line input. Press Ctrl-C to stop (or wait 15s for timeout).
- Feedback from this app is sent to stderr.
- Decoding results are sent to stdout.
- Tip: Redirect stdout to a file for multiple input lines.
```
Not shown is the copy/pasted content with Safe Links encoded URLs interspersed
(e.g., right-click pasted into console).
#### Using standard input (e.g., "piping")
```console
$ cat file.with.mixed.text.content | dsl
tacos are great https://go.dev/dl/ but so are cookies http://example.com
```
```console
$ echo 'SafeLinksURLHere' | dsl
https://go.dev/dl/
```
```console
$ dsl < file.with.mixed.text.content > decoded-output.txt
tacos are great https://go.dev/dl/ but so are cookies http://example.com
```
#### Using filename flag
> [!NOTE]
> 🛠️ This feature is not implemented but may be added in the future.
### `dslg` tool
1. Launch application
1. Copy single URL or mix of URLs and text (e.g., copying an email) into the
input field
1. Press `Decode` button
1. Press `Copy to Clipboard` button
1. Paste decoded text where needed (e.g., a ticket)
> [!WARNING]
> The `Copy to Clipboard` action does *not* preserve any existing clipboard content; there is no undo for using this button
### `eslg` tool
1. Launch application
1. Copy single unencoded URL or mix of unencoded URLs and text (e.g., copying
an email) into the input field
1. Press one of the desired "action" buttons
- `Encode All`
- `Encode Randomly`
- `QueryEscape All`
- `QueryEscape Randomly`
1. Press `Copy to Clipboard` button
1. Paste transformed text where needed (e.g., a new `testdata` file)
> [!WARNING]
> The `Copy to Clipboard` action does *not* preserve any existing clipboard content; there is no undo for using this button
## License
See the [LICENSE](LICENSE) file for details.
## References
### General
-
-
-
-
-
-
### Observed safelinks.protection.outlook.com subdomains
The following `*.safelinks.protection.outlook.com` subdomains have been found
listed on various KB articles and forums:
- `emea01`
-
- `eur04`
-
- `na01`
-
- `nam01`
-
-
- `nam02`
-
-
- `nam04`
-
- `nam10`
-
- `nam11`
-
- `nam12`
-
### Alternative decoders
The following alternative tools were encountered while researching valid Safe
Links subdomains. These tools are listed here for informational purposes; no
endorsement is implied.
> [!IMPORTANT]
> No guarantees are made regarding the functionality or privacy policies of the following online or local tools. YMMV.
Online decoders:
-
-
-
-
-
-
-
-
Local decoders:
-
-
-
[repo-url]: "This project's GitHub repo"
[releases-url]: "This project's releases"
[go-docs-download]: "Download Go"
[go-docs-install]: "Install Go"
[go-supported-releases]: "Go Release Policy"