• 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

Microsoft uncovers macOS flaw allowing bypass TCC protections and exposing sensitive data

 | 

U.S. CISA adds Cisco ISE and PaperCut NG/MF flaws to its Known Exploited Vulnerabilities catalog

 | 

Critical WordPress Post SMTP plugin flaw exposes 200K+ sites to full takeover

 | 

Scattered Spider targets VMware ESXi in using social engineering

 | 

China-linked group Fire Ant exploits VMware and F5 flaws since early 2025

 | 

Allianz Life data breach exposed the data of most of its 1.4M customers

 | 

SECURITY AFFAIRS MALWARE NEWSLETTER ROUND 55

 | 

Security Affairs newsletter Round 534 by Pierluigi Paganini – INTERNATIONAL EDITION

 | 

Law enforcement operations seized BlackSuit ransomware gang’s darknet sites

 | 

Arizona woman sentenced for aiding North Korea in U.S. IT job fraud scheme

 | 

Operation CargoTalon targets Russia’s aerospace with EAGLET malware,

 | 

Unpatched flaw in EoL LG LNV5110R cameras lets hackers gain Admin access

 | 

Koske, a new AI-Generated Linux malware appears in the threat landscape

 | 

Mitel patches critical MiVoice MX-ONE Auth bypass flaw

 | 

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

 | 
  • 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
  • Cyber Crime
  • Hacking
  • Malware

Pierluigi Paganini July 17, 2019

Threat actors used the Extembro DNS-changer Trojan in an adware campaign to prevent users from accessing security-related websites.

Security experts at Malwarebytes observed an adware campaign that involved the Extembro DNS-changer Trojan to prevent users from accessing websites of security vendors.

“Recently, we uncovered a new DNS-changer called Extenbro that comes with an adware bundler. These DNS-changers block access to security-related sites, so the adware victims can’t download and install security software to get rid of the pests.” reads the post published by Malwarebytes.

The Extenbro Trojan is delivered by a bundler that is tracked by the security firm as Trojan.IStartSurf.

The Extenbro Trojan is used to change the DNS settings, victims can only notice that it adds four DNS servers to the Advanced DNS tab in Windows.

extenbro trojan

To malware gain persistence by creating a randomly-named Scheduled Task that points to a fixed-location folder.

The Extenbro Trojan adds a certificate to the set of Windows Root certificates, it has no “Friendly Name” and experts believe it was registered to abose[at]reddit[dot]com.

The malware also disables IPv6 by changing the registry value DisabledComponents under the key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\TCPIP6\Parameters. Thus, it forces the system to use the new DNS servers.

On top of that, the Trojan makes a change in the Firefox user.js file and configures the browser to use the Windows Certificate Store where its root certificate was added.

The Extenbro Trojan also modifies the Firefox user.js file and sets the security.enterprise_roots.enabled setting to true, in this way it forces Firefox to use the Windows Certificate Store that includes the newly-added root certificate.

The analysis published by Malwarebytes includes the removal instructions.

To restore their DNS settings, users should remove the DNS entries added by the malware from the DNS advanced settings without rebooting the system.

“To get to your security sites, you may need a restart of the browser. Do NOT reboot your system or the DNS servers might be changed for the worse again by the Scheduled Task that belongs to the Trojan. If your existing solution does not pick up on the malware, download  Malwarebytes to your desktop.” concludes the analysis.

To restore Firefox to the initial settings, users should type about:config in the address bar, search for security.enterprise_roots.enabled and change it to the default setting, “False.”

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

Pierluigi Paganini

(SecurityAffairs – Extembro Trojan, adware)

[adrotate banner=”5″]

[adrotate banner=”13″]


facebook linkedin twitter

adware campaign Extembro Trojan Hacking hacking news information security news malware Pierluigi Paganini Security Affairs Security News

you might also like

Pierluigi Paganini July 29, 2025
Microsoft uncovers macOS flaw allowing bypass TCC protections and exposing sensitive data
Read more
Pierluigi Paganini July 28, 2025
U.S. CISA adds Cisco ISE and PaperCut NG/MF flaws to its Known Exploited Vulnerabilities catalog
Read more

leave a comment

newsletter

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

    recent articles

    Microsoft uncovers macOS flaw allowing bypass TCC protections and exposing sensitive data

    Hacking / July 29, 2025

    U.S. CISA adds Cisco ISE and PaperCut NG/MF flaws to its Known Exploited Vulnerabilities catalog

    Security / July 28, 2025

    Critical WordPress Post SMTP plugin flaw exposes 200K+ sites to full takeover

    Security / July 28, 2025

    Scattered Spider targets VMware ESXi in using social engineering

    Cyber Crime / July 28, 2025

    China-linked group Fire Ant exploits VMware and F5 flaws since early 2025

    Hacking / July 28, 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