(CLI) Utilities

While UI-based applications are great, sometimes it's just easier to do things from the commandline!

On this page, you'll find various CLI utilities that can be used for spelunking around macOS, or that can facilitate malware analysis:

ProcessMonitor

FileMonitor

DNSMonitor

ProcessMonitor

Download

Leveraging Apple's new Endpoint Security Framework, this utility monitors process creations and terminations, providing detailed information about such events.

              
              Supported OS: macOS 10.15+
            
                Current version: 1.5.0 (change log) 
            
                Zip's SHA-1: B2822859F8E23DE09F212805C2DE0B8E13EEB843 
            
                Source Code: ProcessMonitor

# ProcessMonitor.app/Contents/MacOS/ProcessMonitor -pretty
{
  "event" : "ES_EVENT_TYPE_NOTIFY_EXEC",
  "process" : {
    "signing info (computed)" : {
      "signatureID" : "com.apple.sleep",
      "signatureStatus" : 0,
      "signatureSigner" : "Apple",
      "signatureAuthorities" : [
        "Software Signing",
        "Apple Code Signing Certification Authority",
        "Apple Root CA"
      ]
    },
    "uid" : 501,
    "arguments" : [
      "sleep",
      "666"
    ],
    "ppid" : 12932,
    "ancestors" : [
      2399,
      1
    ],
    "rpid" : 2399,
    "architecture" : "Apple Silicon",
    "path" : "/bin/sleep",
    "signing info (reported)" : {
      "teamID" : "",
      "csFlags" : 570506001,
      "signingID" : "com.apple.sleep",
      "platformBinary" : 1,
      "cdHash" : "1A3D80157484AF62CD5A82190129122958EB1814"
    },
    "name" : "sleep",
    "pid" : 22867
  },
  "timestamp" : "2020-12-16 22:26:40 +0000"
}

Prerequisites

ProcessMonitor leverages Apple's new Endpoint Security Framework to capture system-wide process events. Due to this fact, and thanks to various new security and privacy features introduced in macOS Catalina (10.15) there are several prerequisites that must be fulfilled before ProcessMonitor will successfully run. These include:

Terminal.app must be granted "Full Disk Access".
Open the System Preferences application, and navigate to the "Securtiy & Privacy" pane, click on "Privacy", scroll down to "Full Disk Access" and authenticate to add /System/Applications/Utilities/Terminal.app:

ProcessMonitor must be run as root.
Via Terminal.app execute ProcessMonitor.app/Contents/MacOS/ProcessMonitor either via sudo or from a root prompt:
```
% sudo ProcessMonitor.app/Contents/MacOS/ProcessMonitor
```

Running ProcessMonitor

Once the prerequisites have been fulfilled, launch ProcessMonitor by executing its binary (ProcessMonitor.app/Contents/MacOS/ProcessMonitor), from the terminal:

# ProcessMonitor.app/Contents/MacOS/ProcessMonitor

{"event":"ES_EVENT_TYPE_NOTIFY_EXEC","timestamp":"2020-12-16 22:27:55 +0000","process":{"pid":22875,"name":"sleep","path":"/bin/sleep","uid":501,"architecture":"Apple Silicon","arguments":["sleep","666"],"ppid":12932,"rpid":2399,"ancestors":[2399,1],"signing info (reported)":{"csFlags":570506001,"platformBinary":1,"signingID":"com.apple.sleep","teamID":"","cdHash":"1A3D80157484AF62CD5A82190129122958EB1814"},"signing info (computed)":{"signatureID":"com.apple.sleep","signatureStatus":0,"signatureSigner":"Apple","signatureAuthorities":["Software Signing","Apple Code Signing Certification Authority","Apple Root CA"]}}}

Note:

Though ProcessMonitor is distributed as an application (in order to satisfy Apple's codesigning and notarization requirements), it is a CLI utility. As such, it should be executed from the commandline, by specifying the path to its application binary:

ProcessMonitor.app/Contents/MacOS/ProcessMonitor

Moreover, it must remain in its application bundle (which contains required codesigining and provisioning profile information).

When executed with the -h or -help flag, ProcessMonitor will display information about its commandline options:

$ ProcessMonitor.app/Contents/MacOS/ProcessMonitor -h

USAGE:
 -h or -help      display this usage info
 -pretty          JSON output is 'pretty-printed'
 -skipApple       ignore Apple (platform) processes 
 -filter <name>   show events matching process name

When executed Process Monitor will output JSON "blobs" to standard out. This output can be controlled by various command line arguments including:

-pretty
JSON output is 'pretty-printed' (beautified).

-skipApple
Ignore process events related to Apple (platform) binaries.

-filter <name>
Show (only) events matching process name.

For more details on creating ProcessMonitor read "Writing a Process Monitor with Apple's Endpoint Security Framework".

File Monitor

Download

Leveraging Apple's new Endpoint Security Framework, this utility monitors file events (such as creation, modifications, and deletions) providing detailed information about such events.

              
              Supported OS: macOS 10.15+
            
              Current version: 1.3.0 (change log) 
            
              Zip's SHA-1: 4BF920D7701C034D499865FC6925C233663F6FD4  
            
              Source Code: FileMonitor

# FileMonitor.app/Contents/MacOS/FileMonitor -pretty
{
  "event" : "ES_EVENT_TYPE_NOTIFY_WRITE",
  "file" : {
    "destination" : "/private/tmp/output.txt",
    "process" : {
      "signing info (computed)" : {
        "signatureID" : "com.apple.TextEdit",
        "signatureStatus" : 0,
        "signatureSigner" : "Apple",
        "signatureAuthorities" : [
          "Software Signing",
          "Apple Code Signing Certification Authority",
          "Apple Root CA"
        ]
      },
      "uid" : 501,
      "arguments" : [

      ],
      "ppid" : 1,
      "ancestors" : [
        1
      ],
      "rpid" : 2404,
      "architecture" : "Apple Silicon",
      "path" : "/System/Applications/TextEdit.app/Contents/MacOS/TextEdit",
      "signing info (reported)" : {
        "teamID" : "",
        "csFlags" : 570522385,
        "signingID" : "com.apple.TextEdit",
        "platformBinary" : 1,
        "cdHash" : "D07DBA4427C55E9E4FF430BDD03E05ACEC7A7197"
      },
      "name" : "TextEdit",
      "pid" : 2404
    }
  },
  "timestamp" : "2020-12-16 22:33:23 +0000"
}

Prerequisites

FileMonitor leverages Apple's new Endpoint Security Framework to capture system-wide process events. Due to this fact, and thanks to various new security and privacy features introduced in macOS Catalina (10.15) there are several prerequisites that must be fulfilled before FileMonitor will successfully run. These include:

Terminal.app must be granted "Full Disk Access".
Open the System Preferences application, and navigate to the "Securtiy & Privacy" pane, click on "Privacy", scroll down to "Full Disk Access" and authenticate to add /System/Applications/Utilities/Terminal.app

FileMonitor must be run as root.
Via Terminal.app execute FileMonitor.app/Contents/MacOS/FileMonitor either via sudo or from a root prompt:
```
% sudo FileMonitor.app/Contents/MacOS/FileMonitor
```

Running FileMonitor

Once the prerequisites have been fulfilled, launch FileMonitor by executing its binary (FileMonitor.app/Contents/MacOS/FileMonitor), from the terminal:

# FileMonitor.app/Contents/MacOS/FileMonitor

{"event":"ES_EVENT_TYPE_NOTIFY_OPEN","timestamp":"2020-12-16 22:36:57 +0000","file":{"destination":"/private/tmp/output.txt","process":{"pid":2404,"name":"TextEdit","path":"/System/Applications/TextEdit.app/Contents/MacOS/TextEdit","uid":501,"architecture":"Apple Silicon","arguments":[],"ppid":1,"rpid":2404,"ancestors":[1],"signing info (reported)":{"csFlags":570522385,"platformBinary":1,"signingID":"com.apple.TextEdit","teamID":"","cdHash":"D07DBA4427C55E9E4FF430BDD03E05ACEC7A7197"},"signing info (computed)":{"signatureID":"com.apple.TextEdit","signatureStatus":0,"signatureSigner":"Apple","signatureAuthorities":["Software Signing","Apple Code Signing Certification Authority","Apple Root CA"]}}}}

Note:

Though FileMonitor is distributed as an application (in order to satisfy Apple's codesigning and notarization requirements), it is a CLI utility. As such, it should be executed from the commandline, by specifying the path to its application binary:

FileMonitor.app/Contents/MacOS/FileMonitor

Moreover, it must remain in its application bundle (which contains required codesigining and provisioning profile information).

When executed with the -h or -help flag, FileMonitor will display information about its commandline options:

$ FileMonitor.app/Contents/MacOS/FileMonitor -h

USAGE:
 -h or -help      display this usage info
 -pretty          JSON output is 'pretty-printed'
 -skipApple       ignore Apple (platform) processes 
 -filter <name>   show events matching process name

When executed FileMonitor will output JSON "blobs" to standard out. This output can be controlled by various command line arguments including:

-pretty
JSON output is 'pretty-printed' (beautified).

-skipApple
Ignore process events related to Apple (platform) binaries.

-filter <name>
Show (only) events matching file or process name.
Note, match is performed on the item (process/file path) suffix.

For more details on creating FileMonitor read "Writing a File Monitor with Apple's Endpoint Security Framework".

DNSMonitor

Download

Leveraging Apple's Network Extension Framework, this utility monitors DNS requests and responses.

              
              Supported OS: macOS 10.15+
            
              Current version: 1.1.1 (change log) 
            
              Zip's SHA-1:42C82A040304340024AB9445375970650CF60187
            
              Source Code: DNSMonitor

% DNSMonitor.app/Contents/MacOS/DNSMonitor
...

PROCESS:
{
  processID = 17357;
  processPath = "/usr/bin/nslookup";
  processSigningID = "com.apple.nslookup";
}

PACKET:
  Xid: 10948
  QR: Query
  Server: -nil-
  Opcode: Standard
  AA: Non-Authoritative
  TC: Non-Truncated
  RD: Recursion desired
  RA: No recursion available 
  Rcode: No error
  Question (1):
  objective-see.org IN A    
  Answer (0):
  Authority (0):
  Additional records (0):

Running DNSMonitor

After copying DNSMonitor to the /Applications directory, launch it by executing its binary (DNSMonitor.app/Contents/MacOS/DNSMonitor) via the Terminal:

% DNSMonitor.app/Contents/MacOS/DNSMonitor -h

DNSMonitor usage:
 -h or -help           Display this usage info
 -json                 Output is formatted as JSON
 -pretty               JSON output is 'pretty-printed'
 -nx                   Block via 'NX' packet
 -block    File of domains / ip addresses to block

When run with no arguments, DNSMonitor will begin monitoring for and printing out DNS packets:

% DNSMonitor.app/Contents/MacOS/DNSMonitor

PROCESS:
{
  processID = 17357;
  processPath = "/usr/bin/nslookup";
  processSigningID = "com.apple.nslookup";
}

PACKET:
  Xid: 10948
  QR: Query
  Server: -nil-
  Opcode: Standard
  AA: Non-Authoritative
  TC: Non-Truncated
  RD: Recursion desired
  RA: No recursion available 
  Rcode: No error
  Question (1):
  objective-see.org IN A    
  Answer (0):
  Authority (0):
  Additional records (0):

When run with the -json command-line option DNS packets will be output as JSON. The -pretty option will cause the JSON to be "pretty printed":

% DNSMonitor.app/Contents/MacOS/DNSMonitor -json -pretty
[{
  "Process" : {
    "processPath" : "\/usr\/bin\/nslookup",
    "processSigningID" : "com.apple.nslookup",
    "processID" : 17493
  },
  "Packet" : {
    "Opcode" : "Standard",
    "QR" : "Query",
    "Questions" : [
      {
        "Question Name" : "objective-see.org",
        "Question Class" : "IN",
        "Question Type" : "A    "
      }
    ],
    "RA" : "No recursion available",
    "Rcode" : "No error",
    "RD" : "Recursion desired",
    "XID" : 63159,
    "TC" : "Non-Truncated",
    "AA" : "Non-Authoritative"
  }
 },
...

Via the -block flag, you can specify the path to file containing domains and IP addresses that DNSMonitor will block. The format of this file should be a JSON array. For example, if you wanted to block DNS resolutions of google either by name or by (one of) its IP addresses:

[
  "google.com",
  "172.217.175.46"
]

Now, once DNSMonitor is off and running with this blocklist (e.g. DNSMonitor.app/Contents/MacOS/DNSMonitor -block blocklist.json), requests, for example to google.com will be blocked, and thus the request will simply timeout:

% nslookup google.com
;; connection timed out; no servers could be reached

Note that by default, to block a DNS query or response, the network flow is simply closed out. However, if you execute DNSMonitor with the -nx flag, it will instead return an "NX" response, indicating that the domain does not exist.

You can also dump DNSMonitor's 'cache', by sending it a -USR1 signal to com.objective-see.dnsmonitor.extension:

# kill -USR1

% DNSMonitor.app/Contents/MacOS/DNSMonitor
Received signal: USR1

Dumping DNS Cache:

google.com:(
  "142.250.176.14"
)

objective-see.org:(
  "185.199.109.153",
  "185.199.110.153"
)
gateway.icloud.com:(
  "17.248.245.38",
  "17.248.245.43",
  "17.248.245.45",
  ...
)

Note:

Though DNSMonitor is distributed as an application (in order to satisfy Apple's codesigning, notarization, and System/Network extension requirements), it is a CLI utility. As such, it should be executed from the commandline, by specifying the path to its application binary:

DNSMonitor.app/Contents/MacOS/DNSMonitor

Moreover, it must remain in its application bundle (which contains required codesigining and provisioning profile information).

DNSMonitor leverages Apple's System/Network Extensions Framework to capture system-wide DNS events. Apple places several restrictions on such extensions. Specifically such extensions must first be copied to the /Applications directory. And the user must manually approve any extension before it is allowed to begin capturing (network) events.

Thus, to run DNSMonitor.app, you must:

Ensure the application bundle DNSMonitor.app, has been copied into the /Applications directory. If not an error will be displayed:

% ~/Downloads/DNSMonitor.app/Contents/MacOS/DNSMonitor 
... 

ERROR: As DNSMonitor uses a System Extension, 
       Apple requires it must be located in /Applications

Approve the System Extension. First, macOS will display a prompt:

Click "Open Security Preferences" to open the System Preferences application (it should load the "Security & Privacy" pane). Click "Allow", then authenticate to allow the DNSMonitor extension to load:

Once the extension has been approved it will load. However, macOS will then request approval to allow it to monitor DNS traffic.
Click "Allow" to allow DNSMonitor to monitor DNS traffic.

Now, all DNS requests and response will be displayed in the terminal.

To terminate DNSMonitor, simply hit control+c. This will trigger a prompt from the operating system to unload the extension:

...authenticate by entering your user name password and click "OK". This will remove DNSMonitor's extension and cause it to cleanly terminate.