\*\*\*\*[**SuspiciousPackage**](https://mothersruin.com/software/SuspiciousPackage/get.html) is a tool useful to inspect **.pkg** files \(installers\) and see what is inside before installing it.
These installers have `preinstall` and `postinstall` bash scripts that malware authors usually abuse to **persist****the****malware**.
### hdiutil
This tool allows to **mount** Apple disk images \(**.dmg**\) files to inspect them before running anything:
When a function is called in a binary that uses objective-C, the compiled code instead of calling that function, it will call **`objc_msgSend`**. Which will be calling the final function:
The params this function expects are:
* The first parameter \(**self**\) is "a pointer that points to the **instance of the class that is to receive the message**". Or more simply put, it’s the object that the method is being invoked upon. If the method is a class method, this will be an instance of the class object \(as a whole\), whereas for an instance method, self will point to an instantiated instance of the class as an object.
* The second parameter, \(**op**\), is "the selector of the method that handles the message". Again, more simply put, this is just the **name of the method.**
* The remaining parameters are any **values that are required by the method** \(op\).
Note that in order to debug binaries, **SIP needs to be disabled** \(`csrutil disable` or `csrutil enable --without debug`\) or to copy the binaries to a temporary folder and **remove the signature** with `codesign --remove-signature <binary-path>` or allow the debugging of the binary \(you can use [this script](https://gist.github.com/carlospolop/a66b8d72bb8f43913c4b5ae45672578b)\)
{% endhint %}
{% hint style="warning" %}
Note that in order to **instrument system binarie**s, \(such as `cloudconfigurationd`\) on macOS, **SIP must be disabled** \(just removing the signature won't work\).
It allows users access to applications at an extremely **low level** and provides a way for users to **trace****programs** and even change their execution flow. Dtrace uses **probes** which are **placed throughout the kernel** and are at locations such as the beginning and end of system calls.
The available probes of dtrace can be obtained with:
```bash
dtrace -l | head
ID PROVIDER MODULE FUNCTION NAME
1 dtrace BEGIN
2 dtrace END
3 dtrace ERROR
43 profile profile-97
44 profile profile-199
```
The probe name consists of four parts: the provider, module, function, and name \(`fbt:mach_kernel:ptrace:entry`\). If you not specifies some part of the name, Dtrace will apply that part as a wildcard.
A more detailed explanation and more examples can be found in [https://illumos.org/books/dtrace/chp-intro.html](https://illumos.org/books/dtrace/chp-intro.html)
#### Examples
* In line
```bash
#Count the number of syscalls of each running process
\*\*\*\*[**ProcessMonitor**](https://objective-see.com/products/utilities.html#ProcessMonitor) is a very useful tool to check the process related actions a process is performing \(for example, monitor which new processes a process is creating\).
\*\*\*\*[**FileMonitor**](https://objective-see.com/products/utilities.html#FileMonitor) allows to monitor file events \(such as creation, modifications, and deletions\) providing detailed information about such events.
ReportCrash **analyzes crashing processes and saves a crash report to disk**. A crash report contains information that can **help a developer diagnose** the cause of a crash.
For applications and other processes **running in the per-user launchd context**, ReportCrash runs as a LaunchAgent and saves crash reports in the user's `~/Library/Logs/DiagnosticReports/`
For daemons, other processes **running in the system launchd context** and other privileged processes, ReportCrash runs as a LaunchDaemon and saves crash reports in the system's `/Library/Logs/DiagnosticReports`
If you are worried about crash reports **being sent to Apple** you can disable them. If not, crash reports can be useful to **figure out how a server crashed**.
[**Checkout this section**](./#file-extensions-apps) ****to find out how you can find which app is responsible of **handling the specified scheme or protocol**.
### Enumerating Network Processes
This interesting to find processes that are managing network data:
