A RAT (remote access Trojan) is malware an attacker uses to gain full administrative privileges and remote control of a target computer. RATs are often downloaded along with seemingly legitimate user-requested programs -- such as video games -- or are sent to their target as an email attachment via a phishing email.
Once the host system is compromised, intruders use a backdoor to control the host, or they may distribute RATs to other vulnerable computers and establish a botnet.
Belonging to the family of Trojan horse viruses, RATs are specifically designed to disguise themselves as legitimate content.
A RAT is typically deployed as a malicious payload using exploit kits, such as Metasploit. Once installed, the RAT gets connected to the command-and-control server, which the hackers control. The hackers achieve this connection by compromising an open TCP port on the target device.
A RAT can also be installed through phishing emails, download packages, web links or torrent files. Users are duped into downloading malicious files through social engineering tactics, or the RAT is installed by threat actors after they gain physical access to a victim's machine, such as through an evil maid attack.
Because a RAT provides a backdoor and enables administrative control, it empowers the intruder to do almost anything on the targeted computer, including the following:
RATs can be difficult to detect because they usually don't show up in lists of running programs or tasks. The actions they perform can be similar to those of legitimate applications. In addition, an intruder often manages the level of resource use so that a drop in performance doesn't alert the user that something is amiss.
Unlike other cybersecurity threat vectors, RATs are dangerous even after they've been removed from a system. They can modify files and hard drives, change data, and record user passwords and codes through keylogging and screen captures, all of which can have long-lasting effects.
The following are some ways a RAT can endanger users, systems and organizations:
The same criteria for threat protection against malware and viruses can also be effective against RATs. The following proactive measures can help mitigate remote access Trojans.
The first step to take after detecting suspicious activity or the presence of a RAT is to disconnect the devices from the network. This prevents additional malicious activity by severing the remote connection of the installed RAT from the attacker.
Keep antivirus software and firewalls up to date, and refrain from downloading programs or opening attachments that aren't from a trusted source. At the administrative level, block unused ports, turn off idle services and monitor outgoing traffic.
Multifactor authentication (MFA) offers an extra layer of security, as two or more authenticators are required before a service grants access. Since most RATs attempt to steal usernames and passwords, setting up and enforcing MFA across the entire organization is an important defense mechanism.
Phishing emails trick unsuspecting users into opening them. Once a malicious link or attachment is opened, it can secretly distribute malware and RATs onto the compromised system. Security awareness training should be provided to all users inside an organization so they can easily spot phishing emails and avoid downloading malicious files and attachments.
An operating system (OS) should always be patched with the latest updates, as they contain fixes for recently observed vulnerabilities, exploits, bugs and malware, including RATs.
An intrusion detection system (IDS) is used for monitoring network traffic and for detecting anomalies or suspicious activities in the network. Even though many RATs have evolved to avoid detection, certain IDSes and advanced persistent threat (APT) tools can be beneficial, as they can detect abnormal patterns of behavior, such as a keyboard and mouse acting strangely or prompting commands on their own.
The principle of least privilege (POLP) is a computer security concept that promotes minimal access to systems and resources. The least amount of privilege that's required for a job is granted initially and is scaled up as needed. The limited access can serve as a roadblock to threat actors from getting full control of a system.
RATs are good at evading detection, and even strong antivirus software can miss them. While only specific scans may detect the presence of a RAT, the following five signs should be observed when searching for a remote access Trojan:
With a plethora of antimalware tools on the market, it can be challenging for organizations to pick the right one for their needs. Read through this antimalware software comparison to find the best option.
20 Oct 2022