• Home
  • Cyber Crime
  • Cyber warfare
  • APT
  • Data Breach
  • Deep Web
  • Digital ID
  • Hacking
  • Hacktivism
  • Intelligence
  • Internet of Things
  • Laws and regulations
  • Malware
  • Mobile
  • Reports
  • Security
  • Social Networks
  • Terrorism
  • ICS-SCADA
  • POLICIES
  • Contact me
MUST READ

Coyote malware is first-ever malware abusing Windows UI Automation

 | 

SonicWall fixed critical flaw in SMA 100 devices exploited in Overstep malware attacks

 | 

DSPM & AI Are Booming: $17.87B and $4.8T Markets by 2033

 | 

Stealth backdoor found in WordPress mu-Plugins folder

 | 

U.S. CISA adds CrushFTP, Google Chromium, and SysAid flaws to its Known Exploited Vulnerabilities catalog

 | 

U.S. CISA urges FCEB agencies to fix two Microsoft SharePoint flaws immediately and added them to its Known Exploited Vulnerabilities catalog

 | 

Sophos fixed two critical Sophos Firewall vulnerabilities

 | 

French Authorities confirm XSS.is admin arrested in Ukraine

 | 

Microsoft linked attacks on SharePoint flaws to China-nexus actors

 | 

Cisco confirms active exploitation of ISE and ISE-PIC flaws

 | 

SharePoint under fire: new ToolShell attacks target enterprises

 | 

CrushFTP zero-day actively exploited at least since July 18

 | 

Hardcoded credentials found in HPE Aruba Instant On Wi-Fi devices

 | 

MuddyWater deploys new DCHSpy variants amid Iran-Israel conflict

 | 

U.S. CISA urges to immediately patch Microsoft SharePoint flaw adding it to its Known Exploited Vulnerabilities catalog

 | 

Microsoft issues emergency patches for SharePoint zero-days exploited in "ToolShell" attacks

 | 

SharePoint zero-day CVE-2025-53770 actively exploited in the wild

 | 

Singapore warns China-linked group UNC3886 targets its critical infrastructure

 | 

U.S. CISA adds Fortinet FortiWeb flaw to its Known Exploited Vulnerabilities catalog

 | 

SECURITY AFFAIRS MALWARE NEWSLETTER ROUND 54

 | 
  • Home
  • Cyber Crime
  • Cyber warfare
  • APT
  • Data Breach
  • Deep Web
  • Digital ID
  • Hacking
  • Hacktivism
  • Intelligence
  • Internet of Things
  • Laws and regulations
  • Malware
  • Mobile
  • Reports
  • Security
  • Social Networks
  • Terrorism
  • ICS-SCADA
  • POLICIES
  • Contact me
  • Home
  • Breaking News
  • Cyber Crime
  • Malware
  • Mobile
  • FluBot malware continues to evolve. What’s new in Version 5.0 and beyond?

FluBot malware continues to evolve. What’s new in Version 5.0 and beyond?

Pierluigi Paganini January 08, 2022

Researchers warn of new campaigns distributing a new improved version of the FluBot malware posing as Flash Player.

Researchers from F5 security are warning of a new enhanced version of the FluBot Android malware that that spread posed as Flash Player. A recent SMISHING campaign spotted by CSIRT KNF, FluBot targeted Polish users with a messaging asking them if to click on a link to view a video. Upon clicking on the link, recipients are redirected to a page offering a fake Flash Player APK that delivers the FluBot malware on the Android device.

⚠️Uwaga!
Dostałeś SMS zachęcający do kliknięcia w link z rzekomo ciekawym filmem?
To próba zainfekowania telefonu złośliwym oprogramowaniem #Flubot, które może wykraść Twoje hasła do Bankowości elektronicznej.
Bądźcie ostrożni! https://t.co/bVxrVWA4oO pic.twitter.com/TCuOvRenyi

— CSIRT KNF (@CSIRT_KNF) January 3, 2022

Flubot has been active since late 2020, it was first observed targeting Spanish users. Since March 2021, the malicious code was also employed in attacks aimed at several European countries as well as Japan.

In March, experts from Swiss security outfit PRODAFT estimated that the number of infected devices worldwide was approximately 60,000. The Android malware has been used to steal banking credentials, payment information, and sensitive data from infected devices.

In past attacks, the malware was spreading by spamming text messages to contacts from infected phones that instruct them to install tainted apps from servers under the control of the attackers.

The malicious code also requests permissions to access the Android Accessibility service, implemented to assist users with disabilities in using Android devices and apps, but that was abused by threat actors to carry out malicious activities.

Since October 2021, threat actors behind the Flubot Android malware are leveraging fake security updates to trick victims into installing the malicious code. The attackers use fake security warnings of Flubot infections and urge them to install the security updates.

The following chart shows the FluBot infection chain, the malicious code start spreading using the initial victim’s contact list.

flubot INFECTION CHAIN
  1. The victim received an SMS message that includes a link to a malicious URL.
  2. The victim clicks the link and is prompted to install an app.
  3. The victim downloads and opens the malicious app that installs FluBot.
  4. FluBot accesses the victim’s contact list and uploads it to the C2 server.
  5. FluBot downloads a list of new contacts to target.
  6. FluBot sends SMS messages to the new list of target contacts, thus propagating FluBot.

According to F5 experts the Flubot version 5.2 includes important improvements, such us the implementation of a a new command, UPDATE_ALT_SEED, to allow operators to change the DGA (domain generation algorithms) seed remotely.

“In version 5.2 a new command, UPDATE_ALT_SEED, is introduced. It enables the attackers to change the DGA (domain generation algorithms) seed remotely. Once such a command is dispatched, FluBot stores the updated seed inside the shared preferences under “g” key.” reads the report published by F5.

The feature allows operators to elude DNS blocklists in an attempt to isolate the C2 infrastructure. Experts also noticed that the new version the DGA mechanism uses 30 top-level domains instead of just three used in previous versions.

In version 4.9, FluBot communicated directly with the server using HTTPS port 443. In FluBot version 5.0, the malware communicates with the C2 server through DNS Tunneling over HTTPS. 

The new version supports a long list of commands including:

  • UPDATE_DNS_SERVERS: New in Version 5.0 –
  • UPDATE_ALT_SEED
  • NOTIF_INT_TOGGLE – Notification Interception
  • GET_SMS: Propagation Through SMS
  • GET_SMS: Propagation Through SMS, Version 5.2
  • RELOAD_INJECTS: Injections and Overlays
  • UPLOAD_SMS: SMS Logging
  • SMS_INT_TOGGLE: SMS Interception
  • GET_CONTACTS: Contact List Logging
  • DISABLE_PLAY_PROTECT
  • Run USSD: Recharge Using Phone Call
  • Disable Battery Optimization
  • Keylogger/Screen Grabber
  • UNINSTALL_APP
  • OPEN_URL: Opens a URL on the Device
  • SEND_SMS: Sends SMS Messages on Demand

For additional technical details about the latest version of the malware give a look at the report that also includes Indicators of Compromise (IoCs).

Follow me on Twitter: @securityaffairs and Facebook

[adrotate banner=”9″][adrotate banner=”12″]

Pierluigi Paganini

(SecurityAffairs – hacking, Flubot)

[adrotate banner=”5″]

[adrotate banner=”13″]


facebook linkedin twitter

Android Cybercrime Hacking hacking news information security news IT Information Security malware Pierluigi Paganini Security Affairs Security News

you might also like

Pierluigi Paganini July 24, 2025
Coyote malware is first-ever malware abusing Windows UI Automation
Read more
Pierluigi Paganini July 24, 2025
SonicWall fixed critical flaw in SMA 100 devices exploited in Overstep malware attacks
Read more

leave a comment

newsletter

Subscribe to my email list and stay
up-to-date!

    recent articles

    Coyote malware is first-ever malware abusing Windows UI Automation

    Malware / July 24, 2025

    SonicWall fixed critical flaw in SMA 100 devices exploited in Overstep malware attacks

    Security / July 24, 2025

    DSPM & AI Are Booming: $17.87B and $4.8T Markets by 2033

    Security / July 24, 2025

    Stealth backdoor found in WordPress mu-Plugins folder

    Malware / July 24, 2025

    U.S. CISA adds CrushFTP, Google Chromium, and SysAid flaws to its Known Exploited Vulnerabilities catalog

    Hacking / July 24, 2025

    To contact me write an email to:

    Pierluigi Paganini :
    pierluigi.paganini@securityaffairs.co

    LEARN MORE

    QUICK LINKS

    • Home
    • Cyber Crime
    • Cyber warfare
    • APT
    • Data Breach
    • Deep Web
    • Digital ID
    • Hacking
    • Hacktivism
    • Intelligence
    • Internet of Things
    • Laws and regulations
    • Malware
    • Mobile
    • Reports
    • Security
    • Social Networks
    • Terrorism
    • ICS-SCADA
    • POLICIES
    • Contact me

    Copyright@securityaffairs 2024

    We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. By clicking “Accept All”, you consent to the use of ALL the cookies. However, you may visit "Cookie Settings" to provide a controlled consent.
    Cookie SettingsAccept All
    Manage consent

    Privacy Overview

    This website uses cookies to improve your experience while you navigate through the website. Out of these cookies, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities...
    Necessary
    Always Enabled
    Necessary cookies are absolutely essential for the website to function properly. This category only includes cookies that ensures basic functionalities and security features of the website. These cookies do not store any personal information.
    Non-necessary
    Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. It is mandatory to procure user consent prior to running these cookies on your website.
    SAVE & ACCEPT