• 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

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

 | 

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

 | 
  • 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
  • APT
  • Breaking News
  • Hacking
  • Security
  • North Korea-linked APT groups actively exploit JetBrains TeamCity flaw

North Korea-linked APT groups actively exploit JetBrains TeamCity flaw

Pierluigi Paganini October 19, 2023

North Korea-linked threat actors are actively exploiting a critical vulnerability CVE-2023-42793 in JetBrains TeamCity.

Microsoft warns that North Korea-linked threat actors are actively exploiting a critical security vulnerability, tracked as CVE-2023-42793 (CVSS score: 9.8), in JetBrains TeamCity.

CVE-2023-42793 is an authentication bypass issue affecting the on-premises version of TeamCity. An attacker can exploit the flaw to steal source code and stored service secrets and private keys of the target organization. By injecting malicious code, an attacker can also compromise the integrity of software releases and impact all downstream users.

In early October, the U.S. Cybersecurity and Infrastructure Security Agency (CISA) added the JetBrains TeamCity to its Known Exploited Vulnerabilities Catalog.

Microsoft attributes the recent attacks to two North Korean APT groups Diamond Sleet and Onyx Sleet, which operate under the Lazarus Group umbrella. 

One of the attack chains detailed by Microsoft was linked to Following Diamond Sleet which compromises TeamCity servers. Then attackers used PowerShell to download two payloads from legitimate infrastructure they had previously compromised. Threat actors deployed the ForestTiger backdoor and used it to dump credentials via the LSASS memory. 

JetBrains TeamCity

In a second cluster linked to Diamond Sleet, threat actors deployed payloads for use in DLL search-order hijacking attacks.

The malicious payloads were used in DLL search-order hijacking attacks to execute a next-stage malware or a remote access trojan (RAT).

JetBrains TeamCity

The Onyx Sleet APT used a different attack chain, threat actors exploited JetBrains TeamCity flaw to create a new user account named krtbgt that’s likely intended to impersonate the Kerberos Ticket Granting Ticket.

Then the threat actor added the account to the Local Administrators Group through net use and ran several system discovery commands on compromised systems.

The state-sponsored hackers were observed deploying a custom proxy tool dubbed HazyLoad.

In some cases, the attackers used the krtbgt account to sign into the compromised device via remote desktop protocol (RDP) and terminate the TeamCity service in a bid to prevent exploitation of the issue by other threat actors.

Threat actors were also spotted deploying tools to retrieve credentials and other data stored by browsers.

Below are the mitigation actions recommended by Microsoft:

  • Apply the update or mitigations released by JetBrains to address CVE-2023-42793.
  • Use the included indicators of compromise to investigate whether they exist in your environment and assess for potential intrusion.
  • Block in-bound traffic from IPs specified in the IOC table.
  • Use Microsoft Defender Antivirus to protect from this threat. Turn on cloud-delivered protection and automatic sample submission. These capabilities use artificial intelligence and machine learning to quickly identify and stop new and unknown threats.
  • Take immediate action to address malicious activity on the impacted device. If malicious code has been launched, the attacker has likely taken complete control of the device. Immediately isolate the system and perform a reset of credentials and tokens.
  • Investigate the device timeline for indications of lateral movement activities using one of the compromised accounts. Check for additional tools that attackers might have dropped to enable credential access, lateral movement, and other attack activities.
  • Ensure that “Safe DLL Search Mode” is set.
  • Turn on the following attack surface reduction rule:
    • Block executable files from running unless they meet a prevalence, age, or trusted list criterion

Follow me on Twitter: @securityaffairs and Facebook and Mastodon

Pierluigi Paganini

(SecurityAffairs – hacking, JetBrains TeamCity)


facebook linkedin twitter

APT Hacking hacking news information security news IT Information Security JetBrains TeamCity North Korea Pierluigi Paganini Security Affairs Security News

you might also like

Pierluigi Paganini July 27, 2025
SECURITY AFFAIRS MALWARE NEWSLETTER ROUND 55
Read more
Pierluigi Paganini July 27, 2025
Security Affairs newsletter Round 534 by Pierluigi Paganini – INTERNATIONAL EDITION
Read more

leave a comment

newsletter

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

    recent articles

    SECURITY AFFAIRS MALWARE NEWSLETTER ROUND 55

    Malware / July 27, 2025

    Security Affairs newsletter Round 534 by Pierluigi Paganini – INTERNATIONAL EDITION

    Breaking News / July 27, 2025

    Law enforcement operations seized BlackSuit ransomware gang’s darknet sites

    Cyber Crime / July 26, 2025

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

    Intelligence / July 26, 2025

    Operation CargoTalon targets Russia’s aerospace with EAGLET malware,

    Intelligence / July 25, 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