Posts Tagged Cyber Attack

What Is Whaling Attack?

PDF Version: What-Is-Whaling-Attack

, , , ,

No Comments

Understanding Everything About GoBrut

GoBrut is a computer virus written in Go programming language. The compilation of GoLang programs generates binaries that have all required dependencies embedded in them. It avoids the need of installed runtimes within the machine and simplifies the multi-platform support of Go applications.

Mode Of Infection

GoBrut virus infects Windows and Linux machines using ‘Brute Force’ method.

What Is Brute Force Infection?

A brute force attack is also known as brute force cracking. It involves a computer machine that tries different combinations of usernames and passwords until it finds the correct combination to unlock the victim machine or network.

There are different types of brute force attacks that can be used by GoBrut virus. Some common types are:

  • Dictionary Attack: The attacker uses a dictionary of possible passwords to guess the right password.
  • Exhaustive Key Search: The computer tries every possible combination of characters to find the correct password. The new computers can brute force crack an 8 character alphanumeric password (including capitals, lowercase letters, numbers, and special characters) in about two hours.
  • Credential Recycling: In this type of attack, the attackers use the leaked usernames and passwords from other data breaches.

The virus is mainly used to target servers running Content Management Systems (CMS) and technologies such as SSH and MySQL. Here is a list of commonly targeted platforms:

Content Management Systems

  • Bitrix
  • Drupal
  • Joomla
  • Magento
  • WordPress
  • OpenCart

Databases

  • MySQL
  • Postgres

Administration Tools

  • SSH
  • FTP
  • cPanel
  • PhpMyAdmin
  • Webhostmanagement

After-Infection Process:

  • After successful infection, the infected system becomes a part of the GoBrut botnet. It now requests work from Command and Control server of the botnet.
  • Once the work is received, the infected host will now bruteforce other systems on the network (mentioned in the work request sent by botnet owner).
  • This allows lateral spread of GoBrut virus in the network.
  • After gaining access to a machine’s credentials, the attackers may steal confidential information, photos or other private data.

As the virus uses brute force techniques to steal password, the machines using low-security passwords are at higher risk of infection. Thus, simple ways to protect a system or network from GoBrut virus are:

  • Use of strong and reliable passwords.
  • Regular update of passwords after short intervals.
  • Avoid use of common passwords for different systems.
  • Apply access control for remote logins across all services.
  • Update all services and plugins regularly to combat vulnerabilities.

For more information on the GoBrut virus, contact Centex Technologies at (254) 213 – 4740.

, , , , ,

No Comments

What Is A Trojan And How To Protect Against It?

A Trojan Virus or Trojan Horse virus is a type of malware that impersonates legitimate files or programs for conceding its true contents. The payload hidden in the Trojan Virus remains unknown to the target user and can act as delivery vehicle for a variety of threats. Unlike normal viruses, a Trojan virus is capable of replicating itself.

Types Of Trojan Virus

Common types of Trojan Virus are:

  • Backdoor Trojans – This type of Trojan Virus allows hackers to remotely access and control a computer for uploading, downloading, or executing files.
  • Exploit Trojans –These Trojans inject a machine with code that is specifically designed to take advantage of vulnerability inherent to a specific piece of software.
  • Rootkit Trojans –These Trojans prevent the discovery of malware already infecting a system so that it can cause maximum damage.
  • Banker Trojans –This type of Trojan Virus specifically targets personal information used for banking and other online transactions.
  • Distributed Denial of Service (DDoS) Trojans – These Trojans are programmed to execute DDoS attacks, where a network or machine is disabled by a flood of requests originating from different sources.
  • Downloader Trojans –These are files written to download additional malware, often including more Trojans, onto an infected system.

Detecting A Trojan Virus:

Some common telltale signs of infection by a Trojan Virus are:

  • Poor Device Performance
  • Strange Device Behavior
  • Pop-Up & Spam Interruptions

If the system exhibits any of these behaviors, it is possible that system is infected with a Trojan Virus. Here are some ways to detect the Trojan:

  • Search the system for programs or applications you don’t remember installing.
  • If you find any unrecognized file names, search online for these file names to check if they are recognized Trojans
  • Scan the system with antivirus and antimalware software to see if it detects a malicious file.

Defending Against Trojan Virus

As preventive measures, stick to following practices to defend your system against Trojan Virus:

  • Install an effective internet security solution
  • Refrain from downloading or installing software from a source you don’t trust
  • Never open an attachment or run a program sent in an email from an unrecognized address
  • Keep all software on your computer up to date with the latest patches for avoiding vulnerabilities
  • Make sure a Trojan antivirus is installed and running on your system
  • Run regular system scans

For more information on Trojan Virus, contact Centex Technologies at (254) 213 – 4740.

, , , ,

No Comments

How Does Fileless Malware Work?

Fileless malware is defined as a type of malicious software that does not rely on virus-laden files to infect a host or victim. In contrast, it makes use of applications that are commonly used to perform legitimate and justified activity for executing malicious code in resident memory of the host. As the software doesn’t create any files, it doesn’t leave any footprints making it difficult to detect and remove.

Key Targets Of Fileless Malware:

The attackers who employ fileless malware tend to gather large amount of information in short span of time. So, they tend to focus the attack on a few key targets. Two systems that form common target are:

  • PowerShell
  • Windows Management Instrumentations

The reasons why attackers choose these systems are:

  • Security technologies trust these utilities
  • Analysts tend to assume that actions of these systems are legitimate
  • These utilities provide complete control over an endpoint
  • Most organizations refrain from shutting down these systems as it will hinder business It or DevOps work

Working Of Fileless Malware:

Following are few scenarios in which fileless malware can use a system’s software, applications and protocols to install and execute malicious activity:

  • Phishing emails, malicious downloads, and links that look legitimate are used as points of entry. Once a user clicks on these links, they load to system’s memory. This enables the hackers to remotely load codes to steal confidential data.
  • Malicious code can be injected into applications that are already installed on the system and trusted by the user. After injecting the code, these applications are hijacked and executed by hackers to carry out malicious activity.
  • Attackers create fake websites that mimic legitimate business pages. When user visits these pages, the websites search for vulnerabilities in Flash plugin. These vulnerabilities are exploited to run malicious code in the browser memory.

Fileless malware is written directly to RAM of the infected system and no changes are made on the hard disk. The malware works in memory and the operations end when the system reboots.

Defending Against Fileless Malware Attacks:

The effective way to defend against fileless malware attacks is to adopt an integrated approach that addresses the entire threat lifecycle. Employing a multi-layer defense protocol enables the user to investigate every phase before, during and after the attack.

For more information on fileless malware and tips on preventing cyber-attacks on computer networks, contact Centex Technologies at (254) 213 – 4740.

, , , ,

No Comments

The New Ryuk Ransomware Attack

Ryuk is a type of crypto-ransomware. It uses encryption as a way to block access to a system or file until the ransom is paid. The ransomware is generally dropped with the help of other malware such as TrickBot or Emotet. Another mode of infection used by Ryuk ransomware is ‘Remote Desk Services’.

The Ryuk attacks were popular in third quarter of 2019, however the ransomware went silent at the onset of COVID-19 quarantine. But, it has returned as new Ryuk ransomware with added features and evolution of tools used to compromise target networks and ransomware deployment.

The most notable feature of new Ryuk ransomware is ‘Speed’. Once a system is infected, the attackers gain access of domain controller and enter early stage of deployment just within a day.

The second notable feature of new Ryuk ransomware is ‘Persistence’. The attackers make multiple attempts by sending renewed phishing emails to establish a contact.

How Is A System Infected?

  • The attackers send a phishing email to the target. The email contains a link, which redirects the user to a malicious document hosted on ‘docs.google.com’.
  • When a user opens the document, its contents are enabled. This allows the document to execute a malicious executable identifier ‘print_document.exe’ as a Buer Loader. Buer Loader is a modular malware-as-a-service downloader.
  • When executed, Buer Loader drops malware files and a Cobalt Strike beacon ‘qoipozincyusury.exe’. it is a modular attack tool which is capable of performing multiple tasks such as providing access to operating system features and establishing a covert command & control channel within the compromised network.
  • Additional Cobalt Strike beacons are downloaded on the system for reconnaissance and to hunt for credentials. Numerous commands are run on the infected system to retrieve information such as list of trusted domains, list of members of ‘enterprise admins’, list of administrators for local machine, list of domain admins, network configuration, etc.
  • Using this data, attackers obtain administrative credentials and connect to domain controller, where they dump data of Active Directory.
  • Using domain administrator credentials, another Cobalt Strike service is installed on the domain controller. It is a chained Server Message Block listener. It allows Cobalt Strike commands to be passed on to the server and other computers on the network. This allows attackers to spread the attack laterally onto other systems in the same network.
  • The Ryuk is launched and it attacks the backup server. In case of detection or interruption by security protocols, the attackers use icacls command to modify access control. This gives them complete control of the system folders on the server.
  • Now, they deploy GMER, a rootkit detector tool. It is used to find and shutdown hidden processes such as antivirus. The ransomware is re-deployed and re-launched multiple times to overwhelm remaining defenses.
  • Ransom notes are dropped in folders hosting the ransomware.

Educate the employees to refrain from opening doubtful emails and documents to prevent the new Ryuk attack.

For more information on the new Ryuk ransomware attack, contact Centex Technologies at (254) 213 – 4740.

, , ,

No Comments