Posts Tagged Malware

Malware: Types, Detection & Prevention

The word ‘Malware’ is derived from the amalgamation of words malicious and software. It is a type of software that is particularly designed with the sole purpose of harming a target computer system by stealing data or causing disruption. In order to stay protected against malware, companies need to use specific anti-malware programs. But before choosing the correct anti-malware system, it is imperative to know about different types of malware.

Following are some common malware types:

  • Virus: A computer virus is malicious code that has the ability to copy itself and spread to other files and folders. The code attaches itself to legitimate executable programs resent in the target system and launch when the program is executed. Some of the harmful functions performed by viruses are modifying or corrupting files, copying data, disrupting software functions, etc. As the virus is self-replicating, it is difficult to completely remove the virus completely.
  • Worms: Worms are self-replicating and infect computers through vulnerabilities in the operating systems. Most worms are designed to consume lot of bandwidth and overload the servers. However, small number of worms can modify the existing files. Worms are used by the hackers to deliver payloads in target systems which are then launched to steal data, corrupt files, etc.
  • Bot: An internet bot is an application designed to perform automatic functions. Hackers can engineer bots to infect computers and perform large scale DDOS attacks. The bots are programmed to infect multiple computer systems and form a botnet to over-flood the server with a large number of requests. Bots are also used to cause inconveniences like spamming and repetitively showing certain advertisements.
  • Ransomware: Ransomware is a malicious software that completely locks the infected system until the user pays a ransom. Ransomware spreads like a worm across a network and has the ability to infect the network of an organization within hours. Some ransomware software do not lock the entire system, but encrypt critical data files. The users are asked to pay a ransom in exchange of decryption key.
  • Spyware: It is a software that lies undetected in the target system. It’s purpose is to collect information on user activity and send it to the hacker’s server. This is done by monitoring usage, logging keystrokes, stealing user passwords, etc.
  • Trojans: A Trojan is a malicious software that is designed to appear as a common, harmless attachment or downloadable file that may not be detected as harmful by the antivirus system. However, once downloaded, the software executes itself and causes damage such as stealing data, erasing or modifying files, altering system configuration, etc.

Detection Of Malware:

Some common signs that indicate presence of malware are:

  • Slowing down of systems
  • Reduced browsing speed
  • Recurrent freezing of systems
  • Modification of files
  • Altered system settings
  • Missing files
  • Random appearance of new files or applications

Prevention Of Malware:

  • Use reliable & authentic anti-virus
  • Conduct regular scans
  • Do not use pirated software
  • Don’t open attachments from unknown sources

For more information on types, detection and prevention of malware, contact Centex Technologies at (254) 213 – 4740.

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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.

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What Is CryptoWall Ransomware?

A ransomware is a type of malware that encrypts user files on victim computer or network. The attacker then demands a ransom from the victim in exchange for the decryption key. CryptoWall is a family of such file-encrypting ransomware. It first appeared in early 2014 and has numerous variants including Cryptorbit, CryptoDefense, CryptoWall 2.0, and CryptoWall 3.0. The early variants used RSA public key for file encryption, however, the new versions use AES key for file encryption. The AES key is further encrypted using a public key. This makes it impossible to get the actual key needed to decrypt the files.

Mode Of Infection:

Traditionally, CryptoWall ransomware was distributed via exploit kits. But, now spam emails are also used to infect the victims. The spam email contains RAR attachment that includes a CHM file. When the victim opens the CHM file, it downloads ‘CryptoWall binary’ to the system and copies itself into the %temp% folder.

CHM file – Compiled HTML or CHM file is an interactive html file that is compressed inside a CHM container and may hold other files such as JavaScript, images, etc. inside it.

Execution:

  • The Cryptowall binary downloaded on the system is compressed or encoded. Useless instructions and anti-emulation tricks are deliberately inserted in the coding to break AV engine protection.
  • On execution, it launches a new instance of explorer.exe process.
  • In the next step, the ransomware injects its unpacked CrytoWall binary and executes the injected code.
  • The original process automatically exits itself after launching the injected explorer process.
  • The files are encrypted and the ransomware deletes the volume shadow files using ‘vssadmin.exe’ tool. This makes sure that the encrypted files may not be recovered.
  • The CryptoWall binary is copied to various locations such as %appdata%, %startup%, %rootdrive%, etc. The copies are added to the auto start key to help them stay persistent even after the infected system is rebooted.
  • A new svchost.exe process is launched with user privilege and malicious binary code is injected into it.
  • The ransomware connects to I2P proxies to find live command and control server.
  • The server replies with unique encryption key generated specifically for the target system. The key starts the file encryption thread and drops ransom notes in all directories.
  • Finally, it launches Internet Explorer to display ransom notes and the hollowed svchost process kills itself.

Protection:

  • Keep antivirus up-to-date
  • Back up the files
  • Apply windows update regularly
  • Avoid clicking random emails
  • Disable remote desktop connections
  • Block binaries running from %appdata% and %temp% paths

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

 

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Data Protection From Malicious VPN Apps

Web users intend to use VPN services with an assumption that VPN keeps their web browsing and personal data safe. However, recent research has thrown light on some vulnerabilities found in common and popular VPN apps.

These vulnerabilities include:

  • Missing encryption of sensitive data.
  • Hard-coded cryptographic keys within the app; thus, even if the data is encrypted, hackers can decrypt it using these keys.
  • Some VPN apps have user privacy breaking bugs such as DNS leaks which expose user DNS queries to their ISPs.

These vulnerabilities of VPN apps allow hackers to intercept user communications including web browsing history, username, passwords, photos, videos, and messages. The privacy breaches include location tracking, access to device status information, use of the camera, microphone access and ability to send SMS secretly. Using these vulnerabilities, hackers can manipulate the users to connect to their malicious VPN servers.

In addition to these vulnerabilities, there are some other concerns associated with free VPN apps:

  • Some free VPN apps sell your bandwidth to paying customers allowing them to use your device’s processing power.
  • Malicious VPN apps incorporate ads that may include malware. These apps may also share the online activity of users to third party marketing professionals.

Some signs that your phone has been affected by malware are:

  • Phone becomes slow.
  • Higher loading time of app.
  • Battery drains faster than usual.
  • Large number of pop-up ads.
  • Unexplainable data usage.

As the number of data breaches is exceeding, it has become important to take necessary measures for safeguarding yourself against malicious VPN apps. Following are some measures that you should take:

  • Check if you have sufficient information about the app developer. Download the VPN apps provided by trusted app developers only.
  • Check the app reviews. You can also search for the app on the search engine to check if there is any controversial news about it.
  • Audit the apps on your phone to check if they were downloaded by you or not.
    Delete apps that you don’t use frequently.
  • Run a malware scan after downloading any app to ensure it is safe.

For more information on ways to protect your data from malicious VPN apps, contact Centex Technologies at (254) 213 – 4740.

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Comprehensive Guide To Mobile Data Security

PDF Version: Comprehensive-Guide-To-Mobile-Data-Security

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