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This section is heavily based on the blog series [**Beyond the good ol' LaunchAgents**](https://theevilbit.github.io/beyond/), the goal is to add **more Autostart Locations** (if possible), indicate **which techniques are still working** nowadays with latest version of macOS (13.4) and to specify the **permissions** needed.
Here you can find start locations useful for **sandbox bypass** that allows you to simply execute something by **writing it into a file** and **waiting** for a very **common****action**, a determined **amount of time** or an **action you can usually perform** from inside a sandbox without needing root permissions.
**`launchd`** is the **first****process** executed by OX S kernel at startup and the last one to finish at shut down. It should always have the **PID 1**. This process will **read and execute** the configurations indicated in the **ASEP****plists** in:
*`/Library/LaunchAgents`: Per-user agents installed by the admin
*`/Library/LaunchDaemons`: System-wide daemons installed by the admin
*`/System/Library/LaunchAgents`: Per-user agents provided by Apple.
*`/System/Library/LaunchDaemons`: System-wide daemons provided by Apple.
When a user logs in the plists located in `/Users/$USER/Library/LaunchAgents` and `/Users/$USER/Library/LaunchDemons` are started with the **logged users permissions**.
The **main difference between agents and daemons is that agents are loaded when the user logs in and the daemons are loaded at system startup** (as there are services like ssh that needs to be executed before any user access the system). Also agents may use GUI while daemons need to run in the background.
```xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN">
<key>RunAtLoad</key><true/><!--Execute at system startup-->
<key>StartInterval</key>
<integer>800</integer><!--Execute each 800s-->
<key>KeepAlive</key>
<dict>
<key>SuccessfulExit</key></false><!--Re-execute if exit unsuccessful-->
<!--If previous is true, then re-execute in successful exit-->
</dict>
</dict>
</plist>
```
There are cases where an **agent needs to be executed before the user logins**, these are called **PreLoginAgents**. For example, this is useful to provide assistive technology at login. They can be found also in `/Library/LaunchAgents`(see [**here**](https://github.com/HelmutJ/CocoaSampleCode/tree/master/PreLoginAgents) an example).
New Daemons or Agents config files will be **loaded after next reboot or using**`launchctl load <target.plist>` It's **also possible to load .plist files without that extension** with `launchctl -F <file>` (however those plist files won't be automatically loaded after reboot).\
To **ensure** that there isn't **anything** (like an override) **preventing** an **Agent** or **Daemon****from****running** run: `sudo launchctl load -w /System/Library/LaunchDaemos/com.apple.smdb.plist`
If a plist is owned by a user, even if it's in a daemon system wide folders, the **task will be executed as the user** and not as root. This can prevent some privilege escalation attacks.
Shell startup files are executed when our shell environment like `zsh` or `bash` is **starting up**. macOS defaults to `/bin/zsh` these days, and **whenever we open `Terminal` or SSH** into the device, this is the shell environment we are placed into. `bash` and `sh` are still available, however they have to be specifically started.
The man page of zsh, which we can read with **`man zsh`** has a long description of the startup files.
Configuring the indicated exploitation and loging-out and loging-in or even rebooting didn't work for me to execute the app. (The app wasn't being executed, maybe it needs to be running when these actions are performed)
In **`~/Library/Preferences`** are store the preferences of the user in the Applications. Some of these preferences can hold a configuration to **execute other applications/scripts**.
So, if the plist of the preferences of the terminal in the system could be overwritten, the the **`open`** functionality can be used to **open the terminal and that command will be executed**.
If you create a [**`.terminal`** script](https://stackoverflow.com/questions/32086004/how-to-use-the-default-terminal-settings-when-opening-a-terminal-file-osx) and opens, the **Terminal application** will be automatically invoked to execute the commands indicated in there. If the Terminal app has some special privileges (such as TCC), your command will be run with those special privileges.
Try it with:
```bash
# Prepare the payload
cat > /tmp/test.terminal <<EOF
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
QuickLook plugins can be executed when you **trigger the preview of a file** (press space bar with the file selected in Finder) and a **plugin supporting that file type** is installed.
It's possible to compile your own QuickLook plugin, place it in one of the previous locations to load it and then go to a supported file and press space to trigger it.
The root user one is stored in **`/private/var/root/Library/Preferences/com.apple.loginwindow.plist`**
## Conditional Sandbox Bypass
{% hint style="success" %}
Here you can find start locations useful for **sandbox bypass** that allows you to simply execute something by **writing it into a file** and **expecting not super common conditions** like specific **programs installed, "uncommon" user** actions or environments.
ls -lR /usr/lib/cron/tabs/ /private/var/at/jobs /etc/periodic/
```
There you can find the regular **cron****jobs**, the **at****jobs** (not very used) and the **periodic****jobs** (mainly used for cleaning temporary files). The daily periodic jobs can be executed for example with: `periodic daily`.
The iTerm2 preferences located in **`~/Library/Preferences/com.googlecode.iterm2.plist`** can **indicate a command to execute** when the iTerm2 terminal is opened.
This setting can be configured in the iTerm2 settings:
If the popular program [**xbar**](https://github.com/matryer/xbar) is installed, it's possible to write a shell script in **`~/Library/Application\ Support/xbar/plugins/`** which will be executed when xbar is started:
[**Hammerspoon**](https://github.com/Hammerspoon/hammerspoon) is an automation tool, that allows **macOS scripting through LUA scripting language**. We can even embed full AppleScript code as well as run shell scripts.
The app looks for a single file, `~/.hammerspoon/init.lua`, and when started the script will be executed.
By default, unless `PermitUserRC no` in `/etc/ssh/sshd_config`, when a user **logins via SSH** the scripts **`/etc/ssh/sshrc`** and **`~/.ssh/rc`** will be executed.
**Login items** can **also** be indicated in using the API [SMLoginItemSetEnabled](https://developer.apple.com/documentation/servicemanagement/1501557-smloginitemsetenabled?language=objc) which will store the configuration in **`/var/db/com.apple.xpc.launchd/loginitems.501.plist`**
If you store a **ZIP** file as a **Login Item** the **`Archive Utility`** will open it and if the zip was for example stored in **`~/Library`** and contained the Folder **`LaunchAgents/file.plist`** with a backdoor, that folder will be created (it isn't by default) and the plist will be added so the next time the user logs in again, the **backdoor indicated in the plist will be executed**.
Another options would be to create the files **`.bash_profile`** and **`.zshenv`** inside the user HOME so if the folder LaunchAgents already exist this technique would still work.
“At tasks” are used to **schedule tasks at specific times**.\
These tasks differ from cron in that **they are one time tasks** t**hat get removed after executing**. However, they will **survive a system restart** so they can’t be ruled out as a potential threat.
The filename contains the queue, the job number, and the time it’s scheduled to run. For example let’s take a loot at `a0001a019bdcd2`.
*`a` - this is the queue
*`0001a` - job number in hex, `0x1a = 26`
*`019bdcd2` - time in hex. It represents the minutes passed since epoch. `0x019bdcd2` is `26991826` in decimal. If we multiply it by 60 we get `1619509560`, which is `GMT: 2021. April 27., Tuesday 7:46:00`.
If we print the job file, we find that it contains the same information we got using `at -c`.
A Folder Action script is executed when the folder to which it is attached has items added or removed, or when its window is opened, closed, moved, or resized:
* Open the folder via the Finder UI
* Add a file to the folder (can be done via drag/drop or even in a shell prompt from a terminal)
* Remove a file from the folder (can be done via drag/drop or even in a shell prompt from a terminal)
* Navigate out of the folder via the UI
There are a couple ways to implement this:
1. Use the [Automator](https://support.apple.com/guide/automator/welcome/mac) program to create a Folder Action workflow file (.workflow) and install it as a service.
2. Right-click on a folder, select `Folder Actions Setup...`, `Run Service`, and manually attach a script.
3. Use OSAScript to send Apple Event messages to the `System Events.app` to programmatically query and register a new `Folder Action.`
Then, open the `Folder Actions Setup` app, select the **folder you would like to watch** and select in your case **`folder.scpt`** (in my case I called it output2.scp):
**Compile a color picker** bundle with your code (you could use [**this one for example**](https://github.com/viktorstrate/color-picker-plus)) and add a constructor (like in the [Screen Saver section](macos-auto-start-locations.md#screen-saver)) and copy the bundle to `~/Library/ColorPickers`.
Then, when the color picker is triggered your should should be aswell.
Note that the binary loading your library has a **very restrictive sandbox**: `/System/Library/Frameworks/AppKit.framework/Versions/C/XPCServices/LegacyExternalColorPickerService-x86_64.xpc/Contents/MacOS/LegacyExternalColorPickerService-x86_64`
Applications can have `Finder Sync Extensions`. This extension will go inside an application that will be executed. Moreover, for the extension to be able to execute its code it **must be signed** with some valid Apple developer certificate, it must be **sandboxed** (although relaxed exceptions could be added) and it must be registered with something like:
Create a new project in Xcode and select the template to generate a new **Screen Saver**. Then, are your code to it, for example the following code to generate logs.
**Build** it, and copy the `.saver` bundle to **`~/Library/Screen Savers`**. Then, open the Screen Saver GUI and it you just click on it, it should generate a lot of logs:
Note that because inside the entitlements of the binary that loads this code (`/System/Library/Frameworks/ScreenSaver.framework/PlugIns/legacyScreenSaver.appex/Contents/MacOS/legacyScreenSaver`) you can find **`com.apple.security.app-sandbox`** you will be **inside the common application sandbox**.
* **Trigger**: A new file with a extension managed by the spotlight plugin is created.
*`/Library/Spotlight/`
* **Trigger**: A new file with a extension managed by the spotlight plugin is created.
* Root required
*`/System/Library/Spotlight/`
* **Trigger**: A new file with a extension managed by the spotlight plugin is created.
* Root required
*`Some.app/Contents/Library/Spotlight/`
* **Trigger**: A new file with a extension managed by the spotlight plugin is created.
* New app required
#### Description & Exploitation
Spotlight is macOS's built-in search feature, designed to provide users with **quick and comprehensive access to data on their computers**.\
To facilitate this rapid search capability, Spotlight maintains a **proprietary database** and creates an index by **parsing most files**, enabling swift searches through both file names and their content.
The underlying mechanism of Spotlight involves a central process named 'mds', which stands for **'metadata server'.** This process orchestrates the entire Spotlight service. Complementing this, there are multiple 'mdworker' daemons that perform a variety of maintenance tasks, such as indexing different file types (`ps -ef | grep mdworker`). These tasks are made possible through Spotlight importer plugins, or **".mdimporter bundles**", which enable Spotlight to understand and index content across a diverse range of file formats.
The plugins or **`.mdimporter`** bundles are located in the places mentioned previously and if a new bundle appear it's loaded within monute (no need to restart any service). These bundles need to indicate which **file type and extensions they can manage**, this way, Spotlight will use them when a new file with the indicated extension is created.
It's possible to **find all the `mdimporters`** loaded running:
```bash
mdimport -L
Paths: id(501) (
"/System/Library/Spotlight/iWork.mdimporter",
"/System/Library/Spotlight/iPhoto.mdimporter",
"/System/Library/Spotlight/PDF.mdimporter",
[...]
```
And for example **/Library/Spotlight/iBooksAuthor.mdimporter** is used to parse these type of files (extensions `.iba` and `.book` among others):
If you check the Plist of other `mdimporter` you might not find the entry **`UTTypeConformsTo`**. Thats because that is a built-in _Uniform Type Identifiers_ ([UTI](https://en.wikipedia.org/wiki/Uniform\_Type\_Identifier)) and it doesn't need to specify extensions.
Moreover, System default plugins always take precedence, so an attacker can only access files that are not otherwise indexed by Apple's own `mdimporters`.
{% endhint %}
To create your own importer you could start with this project: [https://github.com/megrimm/pd-spotlight-importer](https://github.com/megrimm/pd-spotlight-importer) and then change the name, the **`CFBundleDocumentTypes`** and add **`UTImportedTypeDeclarations`** so it supports the extension you would like to support and refelc them in **`schema.xml`**.\
Then **change** the code of the function **`GetMetadataForFile`** to execute your payload when a file with the processed extension is created.
Finally **build and copy your new `.mdimporter`** to one of thre previous locations and you can chech whenever it's loaded **monitoring the logs** or checking **`mdimport -L.`**
Here you can find start locations useful for **sandbox bypass** that allows you to simply execute something by **writing it into a file** being **root** and/or requiring other **weird conditions.**
The periodic scripts (**`/etc/periodic`**) are executed because of the **launch daemons** configured in `/System/Library/LaunchDaemons/com.apple.periodic*`. Note that scripts stored in `/etc/periodic/` are **executed** as the **owner of the file,** so this won't work for a potential privilege escalation.
Note that the periodic script will be **executed as the owner of the script**. So if a regular user owns the script, it will be executed as that user (this might prevent privilege escalation attacks).
As PAM is more focused in **persistence** and malware that on easy execution inside macOS, this blog won't give a detailed explanation, **read the writeups to understand this technique better**.
You can create an authorization plugin that will be executed when a user logs-in to maintain persistence. For more information about how to create one of these plugins check the previous writeups (and be careful, a poorly written one can lock you out and you will need to clean your mac from recovery mode).
The **`evaluate-mechanisms`** will tell the authorization framework that it will need to **call an external mechanism for authorization**. Moreover, **`privileged`** will make it be executed by root.
The config file **`/private/etc/man.conf`** indicate the binary/script to use when opening man documentation files. So the path to the executable could be modified so anytime the user uses man to read some docs a backdoor is executed.
LoadModule my_custom_module /Users/Shared/example.dylib "My Signature Authority"
```
{% endcode %}
This way your compiled moduled will be loaded by Apache. The only thing is that either you need to **sign it with a valid Apple certificate**, or you need to **add a new trusted certificate** in the system and **sign it** with it.
Then, if needed , to make sure the server will be started you could execute:
A **StartupItem** is a **directory** that gets **placed** in one of these two folders. `/Library/StartupItems/` or `/System/Library/StartupItems/`
After placing a new directory in one of these two locations, **two more items** need to be placed inside that directory. These two items are a **rc script****and a plist** that holds a few settings. This plist must be called “**StartupParameters.plist**”.
{% tabs %}
{% tab title="StartupParameters.plist" %}
```xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plistversion="1.0">
<dict>
<key>Description</key>
<string>This is a description of this service</string>
<key>OrderPreference</key>
<string>None</string><!--Other req services to execute before this -->
<key>Provides</key>
<array>
<string>superservicename</string><!--Name of the services provided by this file -->
Apple introduced a logging mechanism called **emond**. It appears it was never fully developed, and development may have been **abandoned** by Apple for other mechanisms, but it remains **available**.
This little-known service may **not be much use to a Mac admin**, but to a threat actor one very good reason would be to use it as a **persistence mechanism that most macOS admins probably wouldn't know** to look for. Detecting malicious use of emond shouldn't be difficult, as the System LaunchDaemon for the service looks for scripts to run in only one place:
XQuartz is **no longer installed in macOS**, so if you want more info check the writeup.
### ~~kext~~
{% hint style="danger" %}
It's so complicated to install kext even as root taht I won't consider this to escape from sandboxes or even for persistence (unless you have an exploit)
{% endhint %}
#### Location
In order to install a KEXT as a startup item, it needs to be **installed in one of the following locations**:
*`/System/Library/Extensions`
* KEXT files built into the OS X operating system.
*`/Library/Extensions`
* KEXT files installed by 3rd party software
You can list currently loaded kext files with:
```bash
kextstat #List loaded kext
kextload /path/to/kext.kext #Load a new one based on path
kextload -b com.apple.driver.ExampleBundle #Load a new one based on path
Apparently the `plist` from `/System/Library/LaunchAgents/com.apple.amstoold.plist` was using this binary while exposing a XPC service... the thing is that the binary didn't exist, so you could place something there and when the XPC service gets called your binary will be called.
<summary><strong>Learn AWS hacking from zero to hero with</strong><ahref="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (HackTricks AWS Red Team Expert)</strong></a><strong>!</strong></summary>
* If you want to see your **company advertised in HackTricks** or **download HackTricks in PDF** Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** 🐦 [**@carlospolopm**](https://twitter.com/carlospolopm)**.**
* **Share your hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
