• 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

Cisco removed the backdoor account from its Unified Communications Manager

 | 

U.S. Sanctions Russia's Aeza Group for aiding crooks with bulletproof hosting

 | 

Qantas confirms customer data breach amid Scattered Spider attacks

 | 

CVE-2025-6554 is the fourth Chrome zero-day patched by Google in 2025

 | 

U.S. CISA adds TeleMessage TM SGNL flaws to its Known Exploited Vulnerabilities catalog

 | 

A sophisticated cyberattack hit the International Criminal Court

 | 

Esse Health data breach impacted 263,000 individuals

 | 

Europol dismantles €460M crypto scam targeting 5,000 victims worldwide

 | 

CISA and U.S. Agencies warn of ongoing Iranian cyber threats to critical infrastructure

 | 

U.S. CISA adds Citrix NetScaler flaw to its Known Exploited Vulnerabilities catalog

 | 

Canada bans Hikvision over national security concerns

 | 

Denmark moves to protect personal identity from deepfakes with new copyright law

 | 

Ahold Delhaize data breach affected over 2.2 Million individuals

 | 

Facebook wants access to your camera roll for AI photo edits

 | 

SECURITY AFFAIRS MALWARE NEWSLETTER ROUND 51

 | 

Security Affairs newsletter Round 530 by Pierluigi Paganini – INTERNATIONAL EDITION

 | 

The FBI warns that Scattered Spider is now targeting the airline sector

 | 

LapDogs: China-nexus hackers Hijack 1,000+ SOHO devices for espionage

 | 

Taking over millions of developers exploiting an Open VSX Registry flaw

 | 

OneClik APT campaign targets energy sector with stealthy backdoors

 | 
  • 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
  • Hacking
  • Attacks on Citrix servers increase after the release of CVE-2019-19781 exploits

Attacks on Citrix servers increase after the release of CVE-2019-19781 exploits

Pierluigi Paganini January 28, 2020

Citrix has released security patches for the recently disclosed CVE-2019-19781 flaw, but the number of attacks on vulnerable systems is increasing.

Last week, Citrix addressed the actively exploited CVE-2019-19781 flaw in Citrix Application Delivery Controller (ADC), Citrix Gateway, and Citrix SD-WAN WANOP appliances.

Important updates on the #CitrixADC, Citrix Gateway vulnerability: (1) Permanent fixes for ADC v11.1 & 12. (2) We have moved forward the availability of permanent fixes for other ADC versions & SD-WAN WANOP from previous target dates. #CVE201919781https://t.co/20c9u3oh8h

— Citrix (@citrix) January 19, 2020

While security researchers were warning of ongoing scans for Citrix Application Delivery Controller (NetScaler ADC) and Citrix Gateway (NetScaler Gateway) servers affected by the CVE-2019-19781 vulnerability, many experts were announcing the availability online of proof-of-concept exploit code ([1, 2]).

Researchers at MDSsec published technical details of the vulnerability along with a video that shows the exploit they have developed, but they decided to not release it to avoid miscreants use it in the wild.

It has been estimated that 80,000 companies in 158 countries are potentially at risk, most of them in the U.S. (38%), followed by the UK, Germany, the Netherlands, and Australia. 

The CVE-2019-19781 vulnerability was discovered by Mikhail Klyuchnikov from Positive Technologies.

The flaw affects ADC and Gateway versions 10.5, 11.1, 12.0, 12.1, and 13.0, as well as SD-WAN WANOP versions 10.2.6 and 11.0.3.

Citrix released on Friday, the final set of permanent fixes for the vulnerability, for ADC and Gateway version 10.5.

“As with the permanent fixes made available for Citrix ADC and Citrix Gateway versions 11.1, 12.0, 12.1, 13.0, and Citrix SD-WAN 4000-WO, 5000-WO, 4100-WO, and 5100-WO earlier this week, these fixes are available to all customers regardless of whether they have an active maintenance contract with Citrix,” reads the post published by Fermin J. Serna, Chief Information Security Officer at Citrix.

Security experts are monitoring a spike in the number of attacks against Citrix servers after that researchers announced the availability online of proof-of-concept exploits for the CVE-2019-19781 flaw in Citrix NetScaler ADC and Citrix NetScaler Gateway servers.

Researchers from FireEye noticed that one of the threat actors involved in the attacks is patching the vulnerable Citrix servers, installing their own backdoor, tracked as NOTROBIN, to clean up other malware infections and to lock out any other threat from exploiting the CVE-2019-19781 Citrix flaw.

The NOTROBIN backdoor was designed to prevent subsequent exploitation of the flaw on Citrix servers and also to establish backdoor access, a circumstance that suggests that attackers are preparing future attacks. 

It is easy to predict that threat actors will continue to target organizations that will delay in applying the permanent patches or the mitigations. Organizations using Citrix appliances could use the tool released by the company to check for any signs of compromise.

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

Pierluigi Paganini

(SecurityAffairs – Citrix, hacking)

[adrotate banner=”5″]

[adrotate banner=”13″]


facebook linkedin twitter

Citrix CVE-2019-19781 Hacking Pierluigi Paganini Security Affairs Security News

you might also like

Pierluigi Paganini July 02, 2025
Cisco removed the backdoor account from its Unified Communications Manager
Read more
Pierluigi Paganini July 02, 2025
U.S. Sanctions Russia's Aeza Group for aiding crooks with bulletproof hosting
Read more

leave a comment

newsletter

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

    recent articles

    Cisco removed the backdoor account from its Unified Communications Manager

    Security / July 02, 2025

    U.S. Sanctions Russia's Aeza Group for aiding crooks with bulletproof hosting

    Cyber Crime / July 02, 2025

    Qantas confirms customer data breach amid Scattered Spider attacks

    Cyber Crime / July 02, 2025

    CVE-2025-6554 is the fourth Chrome zero-day patched by Google in 2025

    Hacking / July 02, 2025

    U.S. CISA adds TeleMessage TM SGNL flaws to its Known Exploited Vulnerabilities catalog

    Hacking / July 02, 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