• 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
  • APT
  • Breaking News
  • Hacking
  • Security
  • North Korea-linked Lazarus APT targets Microsoft IIS servers to deploy malware

North Korea-linked Lazarus APT targets Microsoft IIS servers to deploy malware

Pierluigi Paganini May 25, 2023

North Korea-linked APT group Lazarus actor has been targeting vulnerable Microsoft IIS servers to deploy malware.

AhnLab Security Emergency response Center (ASEC) researchers reported that the Lazarus APT Group is targeting vulnerable versions of Microsoft IIS servers in a recent wave of malware-based attacks.

Once discovered a vulnerable ISS server, the attackers leverage the DLL side-loading (T1574.002) technique to execute a malicious DLL (msvcr100.dll) that they have placed in the same folder path as a normal application (Wordconv.exe). Then the library is executed via the Windows IIS web server process.

The msvcr100.dll is contained within the import DLL list of Wordconv.exe, this means that the first DLL is loaded in the memory of the Wordconv.exe process when it is executed.

Lazarus ISS attack

“the functionality of msvcr100.dll involves decrypting an encoded PE file (msvcr100.dat) and the key (df2bsr2rob5s1f8788yk6ddi4x0wz1jq) that is transmitted as a command-line argument during the execution of Wordconv.exe by utilizing the Salsa20 algorithm.” reads the analysis published by ASEC. “The decrypted PE file is then executed in the memory. It then performs the function of clearing the malicious DLL module that was loaded through the FreeLibraryAndExitThread WinAPI call before deleting itself (msvcr100.dll).”

The researchers noticed important similarities between the msvcr100.dll and the cylvc.dll previously detailed by ASEC and related to another Lazarus campaign.

The threat actor exploited an open-source Notepad++ plugin called Quick Color Picker (a discontinued project) to establish a foothold in the target network before creating additional malware (diagn.dll).

The diagn.dll received the PE file encoded with the RC6 algorithm as an execution argument value, then uses an internally hard-coded key to decrypt the data file and execute the PE file directly in the memory.

The researchers were not able to determine the malicious behavior of the PE file because the PE data file that was encoded during the attack could not be collected, but the analysis of the log suggests threat the attackers had executed a credential theft tool such as Mimikatz.

Once obtained the system credentials, the threat actor performed internal reconnaissance and used remote access (port 3389) to perform lateral movement into the internal network.

“The Lazarus group used a variety of attack vectors to perform their initial breach, including Log4Shell,  public certificate vulnerability, 3CX supply chain attack, etc.” concludes the report that also provides Indicators of Compromise (IoCs). “since the threat group primarily utilizes the DLL side-loading technique during their initial infiltrations, companies should proactively monitor abnormal process execution relationships and take preemptive measures to prevent the threat group from carrying out activities such as information exfiltration and lateral movement.”

This week, the US Department of the Treasury’s Office of Foreign Assets Control (OFAC) announced sanctions against four entities and one individual for their role in malicious cyber operations conducted to support the government of North Korea.

We are in the final!

Please vote for Security Affairs (https://securityaffairs.com/) as the best European Cybersecurity Blogger Awards 2022 – VOTE FOR YOUR WINNERS
Vote for me in the sections where is reported Securityaffairs or my name Pierluigi Paganini

Please nominate Security Affairs as your favorite blog.

Nominate Pierluigi Paganini and Security Affairs here here: https://docs.google.com/forms/d/e/1FAIpQLSepvnj8b7QzMdLh7vWEDQDqohjBUsHyn3x3xRdYGCetwVy2DA/viewform

Follow me on Twitter: @securityaffairs and Facebook and Mastodon

Pierluigi Paganini

(SecurityAffairs – hacking, DPRK)


facebook linkedin twitter

APT Hacking hacking news IIS information security news IT Information Security Lazarus malware 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