From ERMAC to Hook: Investigating the technical differences between two Android malware variants
Authored by Joshua Kamp (main author) and Alberto Segura.
Summary
Hook and ERMAC are Android based malware families that are both advertised by the actor named “DukeEugene”. Hook is the latest variant to be released by this actor and was first announced at the start of 2023. In this announcement, the actor claims that Hook was written from scratch [1]. In our research, we have analysed two samples of Hook and two samples of ERMAC to further examine the technical differences between these malware families.
After our investigation, we concluded that the ERMAC source code was used as a base for Hook. All commands (30 in total) that the malware operator can send to a device infected with ERMAC malware, also exist in Hook. The code implementation for these commands is nearly identical. The main features in ERMAC are related to sending SMS messages, displaying a phishing window on top of a legitimate app, extracting a list of installed applications, SMS messages and accounts, and automated stealing of recovery seed phrases for multiple cryptocurrency wallets.
Hook has introduced a lot of new features, with a total of 38 additional commands when comparing the latest version of Hook to ERMAC. The most interesting new features in Hook are: streaming the victim’s screen and interacting with the interface to gain complete control over an infected device, the ability to take a photo of the victim using their front facing camera, stealing of cookies related to Google login sessions, and the added support for stealing recovery seeds from additional cryptocurrency wallets.
Hook had a relatively short run. It was first announced on the 12th of January 2023, and the closing of the project was announced on April 19th, 2023, due to “leaving for special military operation”. On May 11th, 2023, the actors claimed that the source code of Hook was sold at a price of $70.000. If these announcements are true, it could mean that we will see interesting new versions of Hook in the future.
The launch of Hook
On the 12th of January 2023, DukeEugene started advertising a new Android botnet to be available for rent: Hook.
Hook malware is designed to steal personal information from its infected users. It contains features such as keylogging, injections/overlay attacks to display phishing windows over (banking) apps (more on this in the “Overlay attacks” section of this blog), and automated stealing of cryptocurrency recovery seeds.
Financial gain seems to be the main motivator for operators that rent Hook, but the malware can be used to spy on its victims as well. Hook is rented out at a cost of $7.000 per month.
The malware was advertised with a wide range of functionality in both the control panel and build itself, and a snippet of this can be seen in the screenshot below.
Command comparison
Analyst’s note: The package names and file hashes that were analysed for this research can be found in the “Analysed samples” section at the end of this blog post.
While checking out the differences in these malware families, we compared the C2 commands (instructions that are sent by the malware operator to the infected device) in each sample. This analysis did lead us to find several new commands and features on Hook, as can be seen just looking at the number of commands implemented in each variant.
| Sample | Number of commands |
| Hook sample #1 | 58 |
| Hook sample #2 | 68 |
| Ermac sample #1 #2 | 30 |
All 30 commands that exist in ERMAC also exist in Hook. Most of these commands are related to sending SMS messages, updating and starting injections, extracting a list of installed applications, SMS messages and accounts, and starting another app on the victim’s device (where cryptocurrency wallet apps are the main target). While simply launching another app may not seem that malicious at first, you will think differently after learning about the automated features in these malware families.
Both Hook and ERMAC contain automated functionality for stealing recovery seeds from cryptocurrency wallets. These can be used to gain access to the victim’s cryptocurrency. We will dive deeper into this feature later in the blog.
When comparing Hook to ERMAC, 29 new commands have been added to the first sample of Hook that we analysed, and the latest version of Hook contains 9 additional commands on top of that. Most of the commands that were added in Hook are related to interacting with the user interface (UI).
Hook command: start_vnc
The UI interaction related commands (such as “clickat” to click on a specific UI element and “longpress” to dispatch a long press gesture) in Hook go hand in hand with the new “start_vnc” command, which starts streaming the victim’s screen.
In the code snippet above we can see that the createScreenCaptureIntent() method is called on the MediaProjectionManager, which is necessary to start screen capture on the device. Along with the many commands to interact with the UI, this allows the malware operator to gain complete control over an infected device and perform actions on the victim’s behalf.
Controls for the malware operator related to the “start_vnc” command.
Command implementation
For the commands that are available in both ERMAC and Hook, the code implementation is nearly identical. Take the “logaccounts” command for example:
This command is used to obtain a list of available accounts by their name and type on the victim’s device. When comparing the code, it’s clear that the logging messages are the main difference. This is the case for all commands that are present in both ERMAC and Hook.
Russian commands
Both ERMAC and the Hook v1 sample that we analysed contain some rather edgy commands in Russian, that do not provide any useful functionality.
The command above translates to “Die_he_who_reversed_this“.
All the Russian commands create a file named “system.apk” in the “apk” directory and immediately deletes it. It appears that the authors have recently adapted their approach to managing a reputable business, as these commands were removed in the latest Hook sample that we analysed.
New commands in Hook V2
In the latest versions of Hook, the authors have added 9 additional commands compared to the first Hook sample that we analysed. These commands are:
| Command | Description |
| send_sms_many | Sends an SMS message to multiple phone numbers |
| addwaitview | Displays a “wait / loading” view with a progress bar, custom background colour, text colour, and text to be displayed |
| removewaitview | Removes the “wait / loading” view that is displayed on the victim’s device because of the “addwaitview” command |
| addview | Adds a new view with a black background that covers the entire screen |
| removeview | Removes the view with the black background that was added by the “addview” command |
| cookie | Steals session cookies (targets victim’s Google account) |
| safepal | Starts the Safepal Wallet application (and steals seed phrases as a result of starting this application, as observed during analysis of the accessibility service) |
| exodus | Starts the Exodus Wallet application (and steals seed phrases as a result of starting this application, as observed during analysis of the accessibility service) |
| takephoto | Takes a photo of the victim using the front facing camera |
One of the already existing commands, “onkeyevent”, also received a new payload option: “double_tap”. As the name suggests, this performs a double tap gesture on the victim’s screen, providing the malware operator with extra functionality to interact with the victim’s device user interface.
More interesting additions are: the support for stealing recovery seed phrases from other crypto wallets (Safepal and Exodus), taking a photo of the victim, and stealing session cookies. Session cookie stealing appears to be a popular trend in Android malware, as we have observed this feature being added to multiple malware families. This is an attractive feature, as it allows the actor to gain access to user accounts without needing the actual login credentials.
Device Admin abuse
Besides adding new commands, the authors have added more functionality related to the “Device Administration API” in the latest version of Hook. This API was developed to support enterprise apps in Android. When an app has device admin privileges, it gains additional capabilities meant for managing the device. This includes the ability to enforce password policies, locking the screen and even wiping the device remotely. As you may expect: abuse of these privileges is often seen in Android malware.
DeviceAdminReceiver and policies
To implement custom device admin functionality in a new class, it should extend the “DeviceAdminReceiver”. This class can be found by examining the app’s Manifest file and searching for the receiver with the “BIND_DEVICE_ADMIN” permission or the “DEVICE_ADMIN_ENABLED” action.
In the screenshot above, you can see an XML file declared as follows: android:resource=”@xml/buyanigetili. This file will contain the device admin policies that can be used by the app. Here’s a comparison of the device admin policies in ERMAC, Hook 1, and Hook 2:
Comparing Hook to ERMAC, the authors have removed the “WIPE_DATA” policy and added the “RESET_PASSWORD” policy in the first version of Hook. In the latest version of Hook, the “DISABLE_KEYGUARD_FEATURES” and “WATCH_LOGIN” policies were added. Below you’ll find a description of each policy that is seen in the screenshot.
| Device Admin Policy | Description |
| USES_POLICY_FORCE_LOCK | The app can lock the device |
| USES_POLICY_WIPE_DATA | The app can factory reset the device |
| USES_POLICY_RESET_PASSWORD | The app can reset the device’s password/pin code |
| USES_POLICY_DISABLE_KEYGUARD_FEATURES | The app can disable use of keyguard (lock screen) features, such as the fingerprint scanner |
| USES_POLICY_WATCH_LOGIN | The app can watch login attempts from the user |
The “DeviceAdminReceiver” class in Android contains methods that can be overridden. This is done to customise the behaviour of a device admin receiver. For example: the “onPasswordFailed” method in the DeviceAdminReceiver is called when an incorrect password is entered on the device. This method can be overridden to perform specific actions when a failed login attempt occurs. In ERMAC and Hook 1, the class that extends the DeviceAdminReceiver only overrides the onReceive() method and the implementation is minimal:
Full implementation of the class to extend the DeviceAdminReceiver in ERMAC. The first version of Hook contains the same implementation.
The onReceive() method is the entry point for broadcasts that are intercepted by the device admin receiver. In ERMAC and Hook 1 this only performs a check to see whether the received parameters are null and will throw an exception if they are.
DeviceAdminReceiver additions in latest version of Hook
In the latest edition of Hook, the class to extend the DeviceAdminReceiver does not just override the “onReceive” method. It also overrides the following methods:
| Device Admin Method | Description |
| onDisableRequested() | Called when the user attempts to disable device admin. Gives the developer a chance to present a warning message to the user |
| onDisabled() | Called prior to device admin being disabled. Upon return, the app can no longer use the protected parts of the DevicePolicyManager API |
| onEnabled() | Called after device admin is first enabled. At this point, the app can use “DevicePolicyManager” to set the desired policies |
| onPasswordFailed() | Called when the user has entered an incorrect password for the device |
| onPasswordSucceeded() | Called after the user has entered a correct password for the device |
When the victim attempts to disable device admin, a warning message is displayed that contains the text “Your mobile is die”.
The fingerprint scanner will be disabled when an incorrect password was entered on the victim’s device. Possibly to make it easier to break into the device later, by forcing the victim to enter their PIN and capturing it.
All keyguard (lock screen) features are enabled again when a correct password was entered on the victim’s device.
Overlay attacks
Overlay attacks, also known as injections, are a popular tactic to steal credentials on Android devices. When an app has permission to draw overlays, it can display content on top of other apps that are running on the device. This is interesting for threat actors, because it allows them to display a phishing window over a legitimate app. When the victim enters their credentials in this window, the malware will capture them.
Both ERMAC and Hook use web injections to display a phishing window as soon as it detects a targeted app being launched on the victim’s device.
In the screenshot above, you can see how ERMAC and Hook set up a WebView component and load the HTML code to be displayed over the target app by calling webView5.loadDataWithBaseURL(null, s6, “text/html”, “UTF-8”, null) and this.setContentView() on the WebView object. The “s6” variable will contain the data to be loaded. The main functionality is the same for both variants, with Hook having some additional logging messages.
The importance of accessibility services
Accessibility Service abuse plays an important role when it comes to web injections and other automated feature in ERMAC and Hook. Accessibility services are used to assist users with disabilities, or users who may temporarily be unable to fully interact with their Android device. For example: users that are driving might need additional or alternative interface feedback. Accessibility services run in the background and receive callbacks from the system when AccessibilityEvent is fired. Apps with accessibility service can have full visibility over UI events, both from the system and from 3rd party apps. They can receive notifications, they can get the package name, list UI elements, extract text, and more. While these services are meant to assist users, they can also be abused by malicious apps for activities such as: keylogging, automatically granting itself additional permissions, and monitoring foreground apps and overlaying them with phishing windows.
When ERMAC or Hook malware is first launched, it prompts the victim with a window that instructs them to enable accessibility services for the malicious app.
A warning message is displayed before enabling the accessibility service, which shows what actions the app will be able to perform when this is enabled.
With accessibility services enabled, ERMAC and Hook malware automatically grants itself additional permissions such as permission to draw overlays. The onAccessibilityEvent() method monitors the package names from received accessibility events, and the web injection related code will be executed when a target app is launched.
Targeted applications
When the infected device is ready to communicate with the C2 server, it sends a list of applications that are currently installed on the device. The C2 server then responds with the target apps that it has injections for. While dynamically analysing the latest version of Hook, we sent a custom HTTP request to the C2 server to make it believe that we have a large amount of apps (700+) installed. For this, we used the list of package names that CSIRT KNF had shared in an analysis report of Hook [2].
The server responded with the list of target apps that the malware can display phishing windows for. Most of the targeted apps in both Hook and ERMAC are related to banking.
Keylogging
Keylogging functionality can be found in the onAccessibilityEvent() method of both ERMAC and Hook. For every accessibility event type that is triggered on the infected device, a method is called that contains keylogger functionality. This method then checks what the accessibility event type was to label the log and extracts the text from it. Comparing the code implementation of keylogging in ERMAC to Hook, there are some slight differences in the accessibility event types that it checks for. But the main functionality of extracting text and sending it to the C2 with a certain label is the same.
The ERMAC keylogger contains an extra check for accessibility event “TYPE_VIEW_SELECTED” (triggered when a user selects a view, such as tapping on a button). Accessibility services can extract information about a selected view, such as the text, and that is exactly what is happening here.
Hook specifically checks for two other accessibility events: the “TYPE_WINDOW_STATE_CHANGED” event (triggered when the state of an active window changes, for example when a new window is opened) or the “TYPE_WINDOW_CONTENT_CHANGED” event (triggered when the content within a window changes, like when the text within a window is updated).
It checks for these events in combination with the content change type
“CONTENT_CHANGE_TYPE_TEXT” (indicating that the text of an UI element has changed). This tells us that the accessibility service is interested in changes of the textual content within a window, which is not surprising for a keylogger.
Stealing of crypto wallet seed phrases
Automatic stealing of recovery seeds from crypto wallets is one of the main features in ERMAC and Hook. This feature is actively developed, with support added for extra crypto wallets in the latest version of Hook.
For this feature, the accessibility service first checks if a crypto wallet app has been opened. Then, it will find UI elements by their ID (such as “com.wallet.crypto.trustapp:id/wallets_preference” and “com.wallet.crypto.trustapp:id/item_wallet_info_action”) and automatically clicks on these elements until it navigated to the view that contains the recovery seed phrase. For the crypto wallet app, it will look like the user is browsing to this phrase by themselves.
Once the window with the recovery seed phrase is reached, it will extract the words from the recovery seed phrase and send them to the C2 server.
The main implementation is the same in ERMAC and Hook for this feature, with Hook containing some extra logging messages and support for stealing seed phrases from additional cryptocurrency wallets.
Replacing copied crypto wallet addresses
Besides being able to automatically steal recovery seeds from opened crypto wallet apps, ERMAC and Hook can also detect whether a wallet address has been copied and replaces the clipboard with their own wallet address. It does this by monitoring for the “TYPE_VIEW_TEXT_CHANGED” event, and checking whether the text matches a regular expression for Bitcoin and Ethereum wallet addresses. If it matches, it will replace the clipboard text with the wallet address of the threat actor.
The wallet addresses that the actors use in both ERMAC and Hook are bc1ql34xd8ynty3myfkwaf8jqeth0p4fxkxg673vlf for Bitcoin and 0x3Cf7d4A8D30035Af83058371f0C6D4369B5024Ca for Ethereum. It’s worth mentioning that these wallet addresses are the same in all samples that we analysed. It appears that this feature has not been very successful for the actors, as they have received only two transactions at the time of writing.
Since the feature has been so unsuccessful, we assume that both received transactions were initiated by the actors themselves. The latest transaction was received from a verified Binance exchange wallet, and it’s unlikely that this comes from an infected device. The other transaction comes from a wallet that could be owned by the Hook actors.
Stealing of session cookies
The “cookie” command is exclusive to Hook and was only added in the latest version of this malware. This feature allows the malware operator to steal session cookies in order to take over the victim’s login session. To do so, a new WebViewClient is set up. When the victim has logged onto their account, the onPageFinished() method of the WebView will be called and it sends the stolen cookies to the C2 server.
All cookie stealing code is related to Google accounts. This is in line with DukeEugene’s announcement of new features that were posted about on April 1st, 2023. See #12 in the screenshot below.
C2 communication protocol
HTTP in ERMAC
ERMAC is known to use the HTTP protocol for communicating with the C2 server, where data is encrypted using AES-256-CBC and then Base64 encoded. The bot sends HTTP POST requests to a randomly generated URL that ends with “.php/” (note that the IP of the C2 server remains the same).
WebSockets in Hook
The first editions of Hook introduced WebSocket communication using Socket.IO, and data is encrypted using the same mechanism as in ERMAC. The Socket.IO library is built on top of the WebSocket protocol and offers low-latency, bidirectional and event-based communication between a client and a server. Socket.IO provides additional guarantees such as fallback to the HTTP protocol and automatic reconnection [3].
The screenshot above shows that the login command was issued to the server, with the user ID of the infected device being sent as encrypted data. The “42” at the beginning of the message is standard in Socket.IO, where the “4” stands for the Engine.IO “message” packet type and the “2” for Socket.IO’s “message” packet type [3].
Mix and match – Protocols in latest versions of Hook
The latest Hook version that we’ve analysed contains the ERMAC HTTP protocol implementation, as well as the WebSocket implementation which already existed in previous editions of Hook. The Hook code snippet below shows that it uses the exact same code implementation as observed in ERMAC to build the URLs for HTTP requests.
Both Hook and ERMAC use the “checkAP” command to check for commands sent by the C2 server. In the screenshot below, you can see that the malware operator sent the “killme” command to the infected device to uninstall Hook. This shows that the ERMAC HTTP protocol is actively used in the latest versions of Hook, together with the already existing WebSocket implementation.
C2 servers
During our investigation into the technical differences between Hook and ERMAC, we have also collected C2 servers related to both families. From these servers, Russia is clearly the preferred country for hosting Hook and ERMAC C2s. We have identified a total of 23 Hook C2 servers that are hosted in Russia.
Other countries that we have found ERMAC and Hook are hosted in are:
- The Netherlands
- United Kingdom
- United States
- Germany
- France
- Korea
- Japan
The end?
On the 19th of April 2023, DukeEugene announced that they are closing the Hook project due to leaving for “special military operation”. The actor mentions that the coder of the Hook project, who goes by the nickname “RedDragon”, will continue to support their clients until their lease runs out.
Two days prior to this announcement, the coder of Hook created a post stating that the source code of Hook is for sale at a price of $70.000. Nearly a month later, on May 11th, the coder asked if the thread could be closed as the source code was sold.
Observations
In the “Replacing copied crypto wallet addresses” section of this blog, we mentioned that the first received transaction comes from an Ethereum wallet address that could possibly be owned by the Hook actors. We noticed that this wallet received a transaction of roughly $25.000 the day after Hook was announced sold. This could be a coincidence, but the fact that this wallet was also the first to send (a small amount of) money to the Ethereum address that is hardcoded in Hook and ERMAC makes us suspect this.
We can’t verify whether the messages from DukeEugene and RedDragon are true. But if they are, we expect to see interesting new forks of Hook in the future.
In this blog we’ve debunked DukeEugene’s statement of Hook being fully developed from scratch. Additionally, in DukeEugene’s advertisement of HookBot we see a screenshot of the Hook panel that seemed to show similarities with ERMAC’s panel.
Conclusion
While the actors of Hook had announced that the malware was written from scratch, it is clear that the ERMAC source code was used as a base. All commands that are present in ERMAC also exist in Hook, and the code implementation of these commands is nearly identical in both malware families. Both Hook and ERMAC contain typical features to steal credentials which are common in Android malware, such as overlay attacks/injections and keylogging. Perhaps a more interesting feature that exists in both malware families is the automated stealing of recovery seeds from cryptocurrency wallets.
While Hook was not written completely from scratch, the authors have added interesting new features compared to ERMAC. With the added capability of being able to stream the victim’s screen and interacting with the UI, operators of Hook can gain complete control over infected devices and perform actions on the user’s behalf. Other interesting new features include the ability to take a photo of the victim using their front facing camera, stealing of cookies related to Google login sessions, and the added support for stealing recovery seeds from additional cryptocurrency wallets.
Besides these new features, significant changes were made in the protocol for communicating with the C2 server. The first versions of Hook introduced WebSocket communication using the Socket.IO library. The latest version of Hook added the HTTP protocol implementation that was already present in ERMAC and can use this next to WebSocket communication.
Hook had a relatively short run. It was first announced on the 12th of January 2023, and the closing of the project was announced on April 19th, 2023, with the actor claiming that he is leaving for “special military operation”. The coder of Hook has allegedly put the source code up for sale at a price of $70,000 and stated that it was sold on May 11th, 2023. If these announcements are true, it could mean that we will see interesting new forks of Hook in the future.
Indicators of Compromise
Analysed samples
| Family | Package name | File hash (SHA-256) |
| Hook | com.lojibiwawajinu.guna | c5996e7a701f1154b48f962d01d457f9b7e95d9c3dd9bbd6a8e083865d563622 |
| Hook | com.wawocizurovi.gadomi | d651219c28eec876f8961dcd0a0e365df110f09b7ae72eccb9de8c84129e23cb |
| ERMAC | com.cazojowiruje.tutado | e0bd84272ea93ea857cc74a745727085cf214eef0b5dcaf3a220d982c89cea84 |
| ERMAC | com.jakedegivuwuwe.yewo | 6d8707da5cb71e23982bd29ac6a9f6069d6620f3bc7d1fd50b06e9897bc0ac50 |
C2 servers
| Family | IP address |
| Hook | 5.42.199[.]22 |
| Hook | 45.81.39[.]149 |
| Hook | 45.93.201[.]92 |
| Hook | 176.100.42[.]11 |
| Hook | 91.215.85[.]223 |
| Hook | 91.215.85[.]37 |
| Hook | 91.215.85[.]23 |
| Hook | 185.186.246[.]69 |
| ERMAC | 5.42.199[.]91 |
| ERMAC | 31.41.244[.]187 |
| ERMAC | 45.93.201[.]92 |
| ERMAC | 92.243.88[.]25 |
| ERMAC | 176.113.115[.]66 |
| ERMAC | 165.232.78[.]246 |
| ERMAC | 51.15.150[.]5 |
| ERMAC | 176.100.42[.]11 |
| ERMAC | 91.215.85[.]22 |
| ERMAC | 35.91.53[.]224 |
| ERMAC | 193.106.191[.]148 |
| ERMAC | 20.249.63[.]72 |
| ERMAC | 62.204.41[.]98 |
| ERMAC | 193.106.191[.]121 |
| ERMAC | 193.106.191[.]116 |
| ERMAC | 176.113.115[.]150 |
| ERMAC | 91.213.50[.]62 |
| ERMAC | 193.106.191[.]118 |
| ERMAC | 5.42.199[.]3 |
| ERMAC | 193.56.146[.]176 |
| ERMAC | 62.204.41[.]94 |
| ERMAC | 176.113.115[.]67 |
| ERMAC | 108.61.166[.]245 |
| ERMAC | 45.159.248[.]25 |
| ERMAC | 20.108.0[.]165 |
| ERMAC | 20.210.252[.]118 |
| ERMAC | 68.178.206[.]43 |
| ERMAC | 35.90.154[.]240 |
Network detection
The following Suricata rules were tested successfully against Hook network traffic:
The second Suricata rule uses an additional Lua script, which can be found here
List of Commands
| Family | Command | Description |
| ERMAC, Hook 1 2 | sendsms | Sends a specified SMS message to a specified number. If the SMS message is too large, it will send the message in multiple parts |
| ERMAC, Hook 1 2 | startussd | Executes a given USSD code on the victim’s device |
| ERMAC, Hook 1 2 | forwardcall | Sets up a call forwarder to forward all calls to the specified number in the payload |
| ERMAC, Hook 1 2 | push | Displays a push notification on the victim’s device, with a custom app name, title, and text to be edited by the malware operator |
| ERMAC, Hook 1 2 | getcontacts | Gets list of all contacts on the victim’s device |
| ERMAC, Hook 1 2 | getaccounts | Gets a list of the accounts on the victim’s device by their name and account type |
| ERMAC, Hook 1 2 | logaccounts | Gets a list of the accounts on the victim’s device by their name and account type |
| ERMAC, Hook 1 2 | getinstallapps | Gets a list of the installed apps on the victim’s device |
| ERMAC, Hook 1 2 | getsms | Steals all SMS messages from the victim’s device |
| ERMAC, Hook 1 2 | startinject | Performs a phishing overlay attack against the given application |
| ERMAC, Hook 1 2 | openurl | Opens the specified URL |
| ERMAC, Hook 1 2 | startauthenticator2 | Starts the Google Authenticator app |
| ERMAC, Hook 1 2 | trust | Launches the Trust Wallet app |
| ERMAC, Hook 1 2 | mycelium | Launches the Mycelium Wallet app |
| ERMAC, Hook 1 2 | piuk | Launches the Blockchain Wallet app |
| ERMAC, Hook 1 2 | samourai | Launches the Samourai Wallet app |
| ERMAC, Hook 1 2 | bitcoincom | Launches the Bitcoin Wallet app |
| ERMAC, Hook 1 2 | toshi | Launches the Coinbase Wallet app |
| ERMAC, Hook 1 2 | metamask | Launches the Metamask Wallet app |
| ERMAC, Hook 1 2 | sendsmsall | Sends a specified SMS message to all contacts on the victim’s device. If the SMS message is too large, it will send the message in multiple parts |
| ERMAC, Hook 1 2 | startapp | Starts the app specified in the payload |
| ERMAC, Hook 1 2 | clearcash | Sets the “autoClickCache” shared preference key to value 1, and launches the “Application Details” setting for the specified app (probably to clear the cache) |
| ERMAC, Hook 1 2 | clearcache | Sets the “autoClickCache” shared preference key to value 1, and launches the “Application Details” setting for the specified app (probably to clear the cache) |
| ERMAC, Hook 1 2 | calling | Calls the number specified in the “number” payload, tries to lock the device and attempts to hide and mute the application |
| ERMAC, Hook 1 2 | deleteapplication | Uninstalls a specified application |
| ERMAC, Hook 1 2 | startadmin | Sets the “start_admin” shared preference key to value 1, which is probably used as a check before attempting to gain Device Admin privileges (as seen in Hook samples) |
| ERMAC, Hook 1 2 | killme | Stores the package name of the malicious app in the “killApplication” shared preference key, in order to uninstall it. This is the kill switch for the malware |
| ERMAC, Hook 1 2 | updateinjectandlistapps | Gets a list of the currently installed apps on the victim’s device, and downloads the injection target lists |
| ERMAC, Hook 1 2 | gmailtitles | Sets the “gm_list” shared preference key to the value “start” and starts the Gmail app |
| ERMAC, Hook 1 2 | getgmailmessage | Sets the “gm_mes_command” shared preference key to the value “start” and starts the Gmail app |
| Hook 1 2 | start_vnc | Starts capturing the victim’s screen constantly (streaming) |
| Hook 1 2 | stop_vnc | Stops capturing the victim’s screen constantly (streaming) |
| Hook 1 2 | takescreenshot | Takes a screenshot of the victim’s device (note that it starts the same activity as for the “start_vnc” command, but it does so without the extra “streamScreen” set to true to only take one screenshot) |
| Hook 1 2 | swipe | Performs a swipe gesture with the specified 4 coordinates |
| Hook 1 2 | swipeup | Perform a swipe up gesture |
| Hook 1 2 | swipedown | Performs a swipe down gesture |
| Hook 1 2 | swipeleft | Performs a swipe left gesture |
| Hook 1 2 | swiperight | Performs a swipe right gesture |
| Hook 1 2 | scrollup | Performs a scroll up gesture |
| Hook 1 2 | scrolldown | Performs a scroll down gesture |
| Hook 1 2 | onkeyevent | Performs a certain action depending on the specified key payload (POWER DIALOG, BACK, HOME, LOCK SCREEN, or RECENTS |
| Hook 1 2 | onpointerevent | Sets X and Y coordinates and performs an action based on the payload text provided. Three options: “down”, “continue”, and “up”. It looks like these payload texts work together, as in: it first sets the starting coordinates where it should press down, then it sets the coordinates where it should draw a line to from the previous starting coordinates, then it performs a stroke gesture using this information |
| Hook 1 2 | longpress | Dispatches a long press gesture at the specified coordinates |
| Hook 1 2 | tap | Dispatches a tap gesture at the specified coordinates |
| Hook 1 2 | clickat | Clicks at a specific UI element |
| Hook 1 2 | clickattext | Clicks on the UI element with a specific text value |
| Hook 1 2 | clickatcontaintext | Clicks on the UI element that contains the payload text |
| Hook 1 2 | cuttext | Replaces the clipboard on the victim’s device with the payload text |
| Hook 1 2 | settext | Sets a specified UI element to the specified text |
| Hook 1 2 | openapp | Opens the specified app |
| Hook 1 2 | openwhatsapp | Sends a message through Whatsapp to the specified number |
| Hook 1 2 | addcontact | Adds a new contact to the victim’s device |
| Hook 1 2 | getcallhistory | Gets a log of the calls that the victim made |
| Hook 1 2 | makecall | Calls the number specified in the payload |
| Hook 1 2 | forwardsms | Sets up an SMS forwarder to forward the received and sent SMS messages from the victim device to the specified number in the payload |
| Hook 1 2 | getlocation | Gets the geographic coordinates (latitude and longitude) of the victim |
| Hook 1 2 | getimages | Gets list of all images on the victim’s device |
| Hook 1 2 | downloadimage | Downloads an image from the victim’s device |
| Hook 1 2 | fmmanager | Either lists the files at a specified path (additional parameter “ls”), or downloads a file from the specified path (additional parameter “dl”) |
| Hook 2 | send_sms_many | Sends an SMS message to multiple phone numbers |
| Hook 2 | addwaitview | Displays a “wait / loading” view with a progress bar, custom background colour, text colour, and text to be displayed |
| Hook 2 | removewaitview | Removes a “RelativeLayout” view group, which displays child views together in relative positions. More specifically: this command removes the “wait / loading” view that is displayed on the victim’s device as a result of the “addwaitview” command |
| Hook 2 | addview | Adds a new view with a black background that covers the entire screen |
| Hook 2 | removeview | Removes a “LinearLayout” view group, which arranges other views either horizontally in a single column or vertically in a single row. More specifically: this command removes the view with the black background that was added by the “addview” command |
| Hook 2 | cookie | Steals session cookies (targets victim’s Google account) |
| Hook 2 | safepal | Starts the Safepal Wallet application (and steals seed phrases as a result of starting this application, as observed during analysis of the accessibility service) |
| Hook 2 | exodus | Starts the Exodus Wallet application (and steals seed phrases as a result of starting this application, as observed during analysis of the accessibility service) |
| Hook 2 | takephoto | Takes a photo of the victim using the front facing camera |
References
[1] – https://www.threatfabric.com/blogs/hook-a-new-ermac-fork-with-rat-capabilities
[2] – https://cebrf.knf.gov.pl/komunikaty/artykuly-csirt-knf/362-ostrzezenia/858-hookbot-a-new-mobile-malware
[3] – https://socket.io/docs/v4/