• 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 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

 | 

Security Affairs newsletter Round 533 by Pierluigi Paganini – INTERNATIONAL EDITION

 | 

Radiology Associates of Richmond data breach impacts 1.4 million people

 | 

Fortinet FortiWeb flaw CVE-2025-25257 exploited hours after PoC release

 | 

Authorities released free decryptor for Phobos and 8base ransomware

 | 

Anne Arundel Dermatology data breach impacts 1.9 million people

 | 

LameHug: first AI-Powered malware linked to Russia’s APT28

 | 

5 Features Every AI-Powered SOC Platform Needs in 2025

 | 

Broadcom patches critical VMware flaws exploited at Pwn2Own Berlin 2025

 | 
  • 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
  • Hacking
  • Security
  • Citrix provides additional measures to address Citrix Bleed

Citrix provides additional measures to address Citrix Bleed

Pierluigi Paganini November 22, 2023

Citrix urges admins to kill NetScaler user sessions after patching their appliances against the CVE-2023-4966 Citrix Bleed vulnerability.

Citrix is providing additional measures to admins who are patching their NetScaler appliances against the CVE-2023-4966 ‘Citrix Bleed‘ vulnerability.

The company is urging admins to drop all active user sessions and terminate all persistent ones. 

“If you are using any of the affected builds listed in the security bulletin, you should upgrade immediately by installing the updated versions.” reads the upgrade to the initial advisory. “After you upgrade, we recommend that you remove any active or persistent sessions using the following commands:

kill aaa session -all

kill icaconnection -all

kill rdp connection -all

kill pcoipConnection -all

clear lb persistentSessions

In late October, Citrix urged administrators to actively secure all NetScaler ADC and Gateway appliances against the CVE-2023-4966 vulnerability, which attackers were exploiting.

On October 10, Citrix published a security bulletin related to the critical vulnerability CVE-2023-4966 in Citrix NetScaler ADC/Gateway devices.

“Exploits of CVE-2023-4966 on unmitigated appliances have been observed.” reported Citrix. “Cloud Software Group strongly urges customers of NetScaler ADC and NetScaler Gateway to install the relevant updated versions of NetScaler ADC and NetScaler Gateway as soon as possible: 

  • NetScaler ADC and NetScaler Gateway 14.1-8.50  and later releases
  • NetScaler ADC and NetScaler Gateway  13.1-49.15  and later releases of 13.1
  • NetScaler ADC and NetScaler Gateway 13.0-92.19 and later releases of 13.0  
  • NetScaler ADC 13.1-FIPS 13.1-37.164 and later releases of 13.1-FIPS  
  • NetScaler ADC 12.1-FIPS 12.1-55.300 and later releases of 12.1-FIPS  
  • NetScaler ADC 12.1-NDcPP 12.1-55.300 and later releases of 12.1-NDcPP 

Note: NetScaler ADC and NetScaler Gateway version 12.1 is now End-of-Life (EOL). Customers are recommended to upgrade their appliances to one of the supported versions that address the vulnerabilities.”

Researchers from Mandiant observed the exploitation of this vulnerability as a zero-day since late August.

Threat actors exploited this vulnerability to hijack existing authenticated sessions and bypass multifactor authentication or other strong authentication requirements. The researchers warn that these sessions may persist even after deploying the update to mitigate CVE-2023-4966.

Mandiant also noted threat actors hijacking sessions, stealing session data before deploying the patch, and subsequently using it.

“The authenticated session hijacking could then result in further downstream access based upon the permissions and scope of access that the identity or session was permitted. A threat actor could utilize this method to harvest additional credentials, laterally pivot, and gain access to additional resources within an environment.” states Mandiant.

The attacks observed by Mandiant aimed at professional services, technology, and government organizations. 

The security firm published the CVE-2023-4966 guidance document for remediating and reducing risks related to this flaw.

The UC CISA warned that both nation-state hackers and cybercriminal gangs are actively exploiting the Citrix Bleed vulnerability. The US agency provided TTPs and IOCs shared by Boeing and related the intrusion attributed to LockBit 3.0 affiliates exploiting CVE-2023-4966.

“The Cybersecurity and Infrastructure Security Agency (CISA), Federal Bureau of Investigation (FBI), Multi-State Information Sharing & Analysis Center (MS-ISAC), and Australian Signals Directorate’s Australian Cyber Security Center (ASD’s ACSC) are releasing this joint Cybersecurity Advisory (CSA) to disseminate IOCs, TTPs, and detection methods associated with LockBit 3.0 ransomware exploiting CVE-2023-4966, labeled Citrix Bleed, affecting Citrix NetScaler web application delivery control (ADC) and NetScaler Gateway appliances.” reads the joint advisory published by CISA.

Follow me on Twitter: @securityaffairs and Facebook and Mastodon

Pierluigi Paganini

(SecurityAffairs – hacking, Citrix)


facebook linkedin twitter

Citrix Bleed Hacking hacking news information security news IT Information Security Pierluigi Paganini Security Affairs Security News

you might also like

Pierluigi Paganini July 23, 2025
Microsoft linked attacks on SharePoint flaws to China-nexus actors
Read more
Pierluigi Paganini July 22, 2025
Cisco confirms active exploitation of ISE and ISE-PIC flaws
Read more

leave a comment

newsletter

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

    recent articles

    Microsoft linked attacks on SharePoint flaws to China-nexus actors

    APT / July 23, 2025

    Cisco confirms active exploitation of ISE and ISE-PIC flaws

    Hacking / July 22, 2025

    SharePoint under fire: new ToolShell attacks target enterprises

    Hacking / July 22, 2025

    CrushFTP zero-day actively exploited at least since July 18

    Hacking / July 22, 2025

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

    Security / July 22, 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