Posts tagged: Trojan

Aug 14 2013

Android Malware Exploiting Google Cloud Messaging Service

Google Cloud Messaging Hacking Researchers have discovered a number of malicious Android apps are using Google’s Cloud Messaging (GCM) service and leveraging it as a command and control server to carry out attacks.

A post on Securelist today by Kaspersky Lab’s Roman Unuchek, breaks down five Trojans that have been spotted checking in with GCM after launching.

  • Trojan-SMS.AndroidOS.FakeInst.a
  • Trojan-SMS.AndroidOS.Agent.ao
  • Trojan-SMS.AndroidOS.OpFake.a
  • Backdoor.AndroidOS.Maxit.a
  • Trojan-SMS.AndroidOS.Agent.az

These trojans having a relatively wide range of functions:

— Sending premium text messages to a specified number
— Sending text messages to a specified number on the contact list
— Performing self-updates
— Stealing text messages
— Deleting incoming text messages that meet the criteria set by the C&C
— Theft of contacts
— Replacing the C&C or GCM numbers
— Stopping or restarting its operations
— Generate shortcuts to malicious sites
— Initiate phone calls
— Collect information about the phone and the SIM card & upload on server

Kaspersky Lab detected millions of installers in over 130 countries and Kaspersky Mobile Security (KMS) blocked attempted installations for these Trojans.

No doubt, GCM is a useful service for legitimate software developers. But virus writers are using Google Cloud Messaging as an additional C&C for their Trojans. Furthermore, the execution of commands received from GCM is performed by the GCM system and it is impossible to block them directly on an infected device.

The only way to cut this channel off from virus writers is to block developer accounts with IDs linked to the registration of malicious programs.

Jan 19 2013

Shylock Banking Trojan Spreads via Skype

Skype TrojanThe home Trojan-banker known as Shylock has just been updated with new functions. According to the CSIS Security Group, during an investigation, researchers found that Shylock is now capable of spreading using the popular Voice over IP service and software application, Skype.

The program was discovered in 2011 that steals online banking credentials and other financial information from infected computers. Shylock, named after a character from Shakespeare’s “The Merchant of Venice”.

Shylock is active in only a few parts of the world. The epicenter of infections is primarily located in the UK.

The Skype replication is implemented with a plugin called “msg.gsm”. This plugin allows the code to spread through Skype and adds the following functionality:

– Sending messages and transferring files
– Clean messages and transfers from Skype history (using sql-lite access to Skype%smain.db )
– Bypass Skype warning/restriction for connecting to Skype (using “findwindow” and “postmessage”)
– Sends request to server: https://a[removed]s.su/tool/skype.php?action=…

Besides from utilizing Skype it will also spread through local shares and removable drives. Basically, the C&C functions allow the attacker to:

– Execute files
– Get cookies
– Inject HTTP into a website
– Setup VNC
– Spread through removable drives
– Uninstall
– Update C&C server list
– Upload files

Shylock is one of the most advanced Trojan-banker currently being used in attacks against home banking systems. The code is constantly being updated and new features are added regularly.

As always for this type of Trojans antivirus detection is low.

Jun 27 2012

The Zemra Bot – New DDoS Attack Pack

Zemra BotA new Distributed Denial of Service (DDoS) crimeware bot known as “Zemra” and detected by Symantec as Backdoor.Zemra. Lately, this threat has been observed performing denial-of-service attacks against organizations with the purpose of extortion. Zemra first appeared on underground forums in May 2012 at a cost of €100.

This crimeware pack is similar to other crime packs, such as Zeus and SpyEye, in that is has a command-and-control panel hosted on a remote server. This allows it to issue commands to compromised computers and act as the gateway to record the number of infections and bots at the attacker’s disposal.

Similar to other crimeware kits, the functionality of Zemra is extensive:

  • 256-bit DES encryption/decryption for communication between server and client
  • DDoS attacks
  • Device monitoring
  • Download and execution of binary files
  • Installation and persistence in checking to ensure infection
  • Propagation through USB
  • Self update
  • Self uninstall
  • System information collection

However, the main functionality is the ability to perform a DDoS attack on a remote target computer of the user’s choosing.

Initially, when a computer becomes infected, Backdoor.Zemra dials home through HTTP (port 80) and performs a POST request sending hardware ID, current user agent, privilege indication (administrator or not), and the version of the OS. This POST request gets parsed by gate.php, which splits out the information and stores it in an SQL database. It then keeps track of which compromised computers are online and ready to receive commands.

Inspection of the leaked code allowed us to identify two types of DDoS attacks that have been implemented into this bot:

  • HTTP flood
  • SYN flood

Symantec added detection for this threat under the name Backdoor.Zemra, which became active on June 25, 2012. To reduce the possibility of being infected by this Trojan, Symantec advises users to ensure that they are using the latest Symantec protection technologies with the latest antivirus definitions installed.

Jan 18 2012

Carberp Trojan Steals e-Cash Vouchers from Facebook Users

A new configuration of the Carberp Trojan that targets Facebook users to commit financial fraud. Unlike previous Facebook attacks designed to steal user credentials from the log-in page, this version attempts to steal money by duping the user into divulging an e-cash voucher.

Carberp replaces any Facebook page the user navigates to with a fake page notifying the victim that his/her Facebook account is “temporarily locked”. The page asks the user for their first name, last name, email, date of birth, password and a Ukash 20 euro (approximately $25 US) voucher number to “confirm verification” of their identity and unlock the account. The page claims the cash voucher will be “added to the user’s main Facebook account balance”, which is obviously not the case. Instead, the voucher number is transferred to the Carberp bot master who presumably uses it as a cash equivalent (Ukash provides anonymity similar to that offered by cash payments), thus effectively defrauding the user of 20 euro/$25.

Carberp Facebook Attack

This clever man-in-the-browser (MitB) attack exploits the trust users have with the Facebook website and the anonymity of e-cash vouchers. Unlike attacks against online banking applications that require transferring money to another account which creates an auditable trail, this new Carberp attack allows fraudsters to use or sell the e-cash vouchers immediately anywhere they are accepted on the internet.

Attacking social networks like Facebook provides cybercriminals with a large pool of victims that can be fairly easily tricked into divulging confidential account information, and even, as illustrated in this case, giving up their cash. With the growing adoption of e-cash on the internet, we expect to see more of these attacks. Like card not present fraud, where cybercriminals use stolen debit and credit card information to make illegal online purchases without the risk of being caught, e-cash fraud is a low risk form of crime. With e-cash, however, it is the account holder not the financial institution who assumes the liability for fraudulent transactions.

Oct 28 2011

Tsunami – Backdoor Trojan for Mac OS X Discovered

OSX/Tsunami.A, an IRC controlled backdoor Trojan for Mac OS X, has been discovered that enables the infected machine to become a bot for Distributed Denial of Service (DDoS) attacks.

The analyzed sample contains a hardcoded list of IRC servers and channel that it attempts to connect to. This client then listens and interprets commands from the channel. The list of accepted commands can be seen in the following comment block from the C source code of the Linux variant.

Linux Tsunami

In addition to enabling DDoS attacks, the backdoor can enable a remote user to download files, such as additional malware or updates to the Tsunami code. The malware can also execute shell commands, giving it the ability to essentially take control of the affected machine.

In terms of functionality, the Mac variant of the backdoor is similar to its older Linux brother, with only the IRC server, channel and password changed and the greatest difference being that it’s a 64-bit Mach-O binary instead of an ELF binary.