XtremeRAT Activity

Using telemetry from the FireEye Dynamic Threat Intelligence (DTI) cloud, we examined 165 XtremeRAT samples from attacks that primarily hit the following sectors:

• Energy, utilities, and petroleum refining
• Financial Services
• High-tech

These incidents include a spectrum of attacks including targeted attacks as well as indiscriminate attacks. Among these XtremeRAT-based attacks, we found that 4 of the 165 samples were used in targeted attacks against the High-Tech sector by threat actors we have called “MoleRats”.

Rather than building custom malware, many threat actors behind targeted attacks use publicly or commercially available remote access Trojans (RATs). This pre-built malware has all the functionality needed to conduct cyber espionage and is controlled directly by humans, who have the ability to adapt to network defenses. As a result, the threat posed by these RATs should not be underestimated.

However, it is difficult to distinguish and correlate the activity of targeted threat actors based solely on their preference to use particular malware — especially, freely available malware. From an analyst’s perspective, it is unclear whether these actors choose to use this type of malware simply out of convenience or in a deliberate effort to blend in with traditional cybercrime groups, who also use these same tools.

There are numerous RATs available for free and for purchase in online forums, chat rooms and market places on the Internet. Most RATs are easy to use and thus attract novices. They are used for a variety of criminal activity, including “sextortion”. [1] The ubiquity of these RATs makes it difficult to determine if a particular security incident is related to a targeted threat, cybercrime or just a novice “script kiddie” causing a nuisance.

Although publicly available RATs are used by a variety of operators with different intents, the activity of particular threat actors can still be tracked by clustering command and control server information as well as the information that is set by the operators in the builder. These technical indicators, combined with context of an incident (such as the timing, specificity and human activity) allow analysts to assess the targeted or non-targeted nature of the threat.

In this post, we examine a publicly available RAT known as XtremeRAT. This malware has been used in targeted attacks as well as traditional cybercrime. During our investigation we found that the majority of XtremeRAT activity is associated with spam campaigns that typically distribute Zeus variants and other banking-focused malware. Why have these traditional cybercrime operators begun to distribute RATs? This seems odd, considering RATs require manual labor as opposed to automated banking Trojans.

Based on our observations we propose one or more of the following possible explanations:

1. Smokescreen
   The operations may be part of a targeted attack that seeks to disguise itself and its possible targets, by using spam services to launch the attacks.
2. Less traditional tools available
   With more crimeware author arrests and/or disappearance of a number of banking Trojan developers, cybercriminals are resorting to using RATs to manually steal data, such as banking and credit card details. [2]
3. Complicated defenses require more versatile tools
   As many traditional banking and financial institutions have improved their security practices, perhaps attackers have had a much more difficult time developing automation in their Trojans to cover all variations of these defenses; as such, RATs provide more versatility and effectiveness, at the expense of scalability.
4. Casting a wider net
   After compromising indiscriminate targets, attackers may dig deeper into specific targets of interest and/or sell off the access rights of the victims’ systems and their data to others.

These possible explanations are not mutually exclusive. One or all of them may be factors in explaining this observed activity.

XtremeRAT

The XtremeRAT was developed by “xtremecoder” and has been available since at least 2010.  Written in Delphi, the code of XtremeRAT is shared amongst several other Delphi RAT projects including SpyNet, CyberGate, and Cerberus. The RAT is available for free; however, the developer charges 350 Euros for the source code.  Unfortunately for xtremecoder, the source code has been leaked online.  The current version is Xtreme 3.6, however, there are a variety of “private” version of this RAT available as well. As such, the official version of this RAT and its many variants are used by a wide variety of actors.

XtremeRAT allows an attacker to:

• Interact with the victim via a remote shell
• Upload/download files
• Interact with the registry
• Manipulate running processes and services
• Capture images of the desktop
• Record from connected devices, such as a webcam or microphone

Moreover, during the build process, the attacker can specify whether to include keylogging and USB infection functions.

Extracting Intelligence

XtremeRAT contains two components: a “client” and a “server”; however, from the attacker’s perspective, these terms have reversed meanings. Specifically, according to the author, the “server” component is the malware that resides on victim endpoints that connect to the “client”, which is operated by the attacker from one or more remote command-and-control (CnC) systems. Due to this confusing and overloaded terminology, we refer to the “server” as a “backdoor” on the victim and the “client” as a remote “controller” operated by the attacker.

XtremeRAT backdoors maintain and reference configuration data that was chosen by the attacker at the time they were built. This data can contain very useful hints to help group attacks and attribute them to actors, similar to what we have previously described in our Poison Ivy whitepaper. [3]

Several versions of XtremeRAT write this configuration data to disk under %APPDATA%\Microsoft\Windows, either directly, or to a directory named after mutex configured by the attacker. When written to disk, the data is RC4 encrypted with a key of either "CYBERGATEPASS" or "CONFIG" for the versions we have analyzed. In both cases, the key is Unicode. The config file has either a “.nfo” or ".cfg" extension depending on the version. XtremeRAT's key scheduling algorithm (KSA) implementation contains a bug wherein it only considers the length of the key string, not including the null bytes between each character, as is found in these Unicode strings. As a result, it only effectively uses the first half of the key. For example, the key “C\x00O\x00N\x00F\x00I\x00G\x00” is 12 bytes long, but the length is calculated as only being 6 bytes long. Because of this, the key that is ultimately used is “C\x00O\x00N\x00”.

The configuration data includes:

• Name of the installed backdoor file
• Directory under which the backdoor file is installed
• Which process it will inject into (if specified)
• CnC information
• FTP information for sending stolen keystroke data to
• Mutex name of the master process,
• ID and group name which are used by the actors for organizational purposes

Because the decrypted configuration data can be reliably located in memory (with only slight variations in its structure from version to version) and because not all versions of XtremeRAT will write their configuration data to disk, parsing memory dumps of infected systems is often the ideal method for extracting intelligence.

We are releasing python scripts we have developed to gather the configuration details for various versions of XtremeRAT from both process memory dumps and the encrypted configuration file on disk. 

Also included in this toolset is a script that decrypts and prints the contents of the log file created by XtremeRAT containing victim keystroke data. This log file is written to the same directory as the config file and has a “.dat” extension. Curiously, this log file is encrypted with a simple two-byte XOR instead of RC4. Later in this blog, we will share some of the configuration details we have extracted during our subsequent analysis.

XtremeRAT Activity

Using telemetry from the FireEye Dynamic Threat Intelligence (DTI) cloud, we examined 165 XtremeRAT samples from attacks that primarily hit the following sectors:

• Energy, utilities, and petroleum refining
• Financial Services
• High-tech

These incidents include a spectrum of attacks including targeted attacks as well as indiscriminate attacks. Among these XtremeRAT-based attacks, we found that 4 of the 165 samples were used in targeted attacks against the High-Tech sector by threat actors we have called “MoleRats”.

PASSWORD : THEMESSIDE

Download Your File Here!

Download Now!

Download will start in 10 seconds.

How To Use?

Many new coming peoples do not know how to use xtreme rat 3.7? I explain you in a simple way. It is very easy to set up and use like other remote access trojans.

It requires a port forwarding feature and dynamic DNS. Open Xtreme rat builder and enter your dynamic DNS, port number and click on build and a payload will build successfully.