Threat Explorer

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02 April 2013
20 August 2013
Systems Affected:
Android.Teelog is a Trojan horse for Android devices that opens a back door and steals information from the compromised device.

Antivirus Protection Dates

  • Initial Rapid Release version 02 April 2013 revision 017
  • Latest Rapid Release version 21 April 2018 revision 037
  • Initial Daily Certified version 02 April 2013 revision 025
  • Latest Daily Certified version 22 April 2018 revision 007
  • Initial Weekly Certified release date 03 April 2013
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.
When the Trojan is being installed, it requests permissions to perform the following actions:
  • Open network connections
  • Prevent processor from sleeping or screen from dimming
  • Access information about networks
  • Access information about the WiFi state
  • Check the phone's current state
  • Read the owner's data
  • Read user's contacts data
  • Write to external storage devices
  • Write to internal storage devices
  • Use the device's mic to record audio
  • Initiate a phone call without using the Phone UI or requiring confirmation from the user
  • Start once the device has finished booting
  • Restart packages
  • Access the camera device
  • Make the phone vibrate
  • Get information about the currently or recently running tasks
  • Modify global audio settings
  • Monitor incoming MMS messages
  • Send SMS messages
  • Broadcast sticky intents
  • Access the list of accounts in Accounts Service
  • Manage the list of accounts in AccountManager
  • Act as AccountAuthenticator for the AccountManager
  • Create new contact data
  • Read sync settings
  • Write sync settings
  • Access location information, such as Cell-ID or WiFi
  • Access location information, such as GPS information
  • Access the list of accounts in Accounts Service
  • Access information about networks
  • Read SMS messages on the device
  • Read or write to the system settings
  • Read or write the secure system settings
  • Write apn settings
  • Mount and unmount file systems for removable storage
  • Monitor, modify, or abort outgoing calls
  • Allow access to low-level power management
  • Allows read/write access to the "properties" table in the checkin database, to change values that get uploaded
  • Change Wi-Fi connectivity state
  • Modify the telephony state - power on, mmi, etc
  • Discover and pair bluetooth devices
  • Connect to paired bluetooth devices
  • Must be required by device administration receiver, to ensure that only the system can interact with it
  • Modify the current configuration
  • Allows MDM to catch push notifications
  • Adds an app icon to the main screen
  • Receive cloud2device (c2d) messages
  • Send billing requests to the Google Play store

The Trojan may also request the following permissions:
  • android.permission.USES_POLICY_FORCE_LOCK


The Trojan generally arrives within a repackaged .apk file from a legitimate application. The package name, publisher, and other details will vary and may be taken directly from the original application.

The Trojan installs itself as a service so that it remains persistent during system reboots.

The Trojan parses SMS with single numbers and collects the following data:

  • Cell ID
  • Location area code
  • Mobile country code
  • Mobile network code
  • Radio type

The Trojan checks the network type (CDMA, EDGE, GPRS) and sends the collected data back through SMS.

The Trojan collects the following information from the compromised device:
  • IMEI
  • IMSI
  • SIM serial number
  • Phone number
  • Build.PODUCT
  • Build.CPU_ABI
  • Build.TAGS
  • Build.MODEL
  • Build.DEVICE
  • Build.DISPLAY
  • Build.BRAND
  • Build.BOARD
  • Build.ID
  • Build.USER

The Trojan collects the following contact information from the compromised device:
  • Phone number
  • Instant messenger user name
  • Address
  • Email address
  • Name
  • Nickname
  • Notes
  • Organization

The Trojan collects the following SMS information from the compromised device:
  • Address
  • Person
  • Body
  • Date
  • Type

The Trojan collects the following call log information from the compromised device:
  • Number
  • Name
  • Date
  • Type
  • Duration

The Trojan collects the following installed application information from the compromised device:
  • packageName
  • firstInstallTime
  • lastUpdateTime

The Trojan encrypts the collected information and writes it to the following location:

The Trojan opens a back door on the compromised computer, connects to the following domain, and obtains parameters:

The Trojan sends the stolen information to the above server through the following File Transfer Protocol:

The Trojan ecrypts the config file and stores it in the following location:


Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

  • Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
  • Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
  • Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
  • Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
  • Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
  • Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
  • If a threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
  • Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
  • Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
  • Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computers using trusted media.
  • Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
  • If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
  • For further information on the terms used in this document, please refer to the Security Response glossary.
You may have arrived at this page either because you have been alerted by your Symantec product about this risk, or you are concerned that your computer has been affected by this risk.

Before proceeding further we recommend that you run a full system scan . If that does not resolve the problem you can try one of the options available below.

If you are a Norton product user, we recommend you try the following resources to remove this risk.

Removal Tool

If you have an infected Windows system file, you may need to replace it using the Windows installation CD .

How to reduce the risk of infection
The following resources provide further information and best practices to help reduce the risk of infection.

If you are a Symantec business product user, we recommend you try the following resources to remove this risk.

Identifying and submitting suspect files
Submitting suspicious files to Symantec allows us to ensure that our protection capabilities keep up with the ever-changing threat landscape. Submitted files are analyzed by Symantec Security Response and, where necessary, updated definitions are immediately distributed through LiveUpdate™ to all Symantec end points. This ensures that other computers nearby are protected from attack. The following resources may help in identifying suspicious files for submission to Symantec.

Removal Tool

If you have an infected Windows system file, you may need to replace it using the Windows installation CD .

How to reduce the risk of infection
The following resource provides further information and best practices to help reduce the risk of infection.
Protecting your business network

The following instructions pertain to all current Symantec antivirus products.

1. Performing a full system scan
How to run a full system scan using your Symantec product

2. Restoring settings in the registry
Many risks make modifications to the registry, which could impact the functionality or performance of the compromised computer. While many of these modifications can be restored through various Windows components, it may be necessary to edit the registry. See in the Technical Details of this writeup for information about which registry keys were created or modified. Delete registry subkeys and entries created by the risk and return all modified registry entries to their previous values.
Writeup By: Alan Neville