• 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

Stellantis probes data breach linked to third-party provider

 | 

FBI alerts public to spoofed IC3 site used in fraud schemes

 | 

EU agency ENISA says ransomware attack behind airport disruptions

 | 

Researchers expose MalTerminal, an LLM-enabled malware pioneer

 | 

Beware: GitHub repos distributing Atomic Infostealer on macOS

 | 

ESET uncovers Gamaredon–Turla collaboration in Ukraine cyberattacks

 | 

SECURITY AFFAIRS MALWARE NEWSLETTER ROUND 63

 | 

Security Affairs newsletter Round 542 by Pierluigi Paganini – INTERNATIONAL EDITION

 | 

A cyberattack on Collins Aerospace disrupted operations at major European airports

 | 

Fortra addressed a maximum severity flaw in GoAnywhere MFT software

 | 

UK police arrested two teen Scattered Spider members linked to the 2024 attack on Transport for London

 | 

ShadowLeak: Radware Uncovers Zero-Click Attack on ChatGPT

 | 

SonicWall warns customers to reset credentials after MySonicWall backups were exposed

 | 

CVE-2025-10585 is the sixth actively exploited Chrome zero-day patched by Google in 2025

 | 

Jaguar Land Rover will extend its production halt into a third week following a cyberattack

 | 

China-linked APT41 targets government, think tanks, and academics tied to US-China trade and policy

 | 

Microsoft and Cloudflare teamed up to dismantle the RaccoonO365 phishing service

 | 

DoJ resentenced former BreachForums admin to three years in prison

 | 

Apple backports fix for actively exploited CVE-2025-43300

 | 

New supply chain attack hits npm registry, compromising 40+ packages

 | 
  • 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
  • Malware
  • New LockFile ransomware gang uses ProxyShell and PetitPotam exploits

New LockFile ransomware gang uses ProxyShell and PetitPotam exploits

Pierluigi Paganini August 21, 2021

A new ransomware gang named LockFile targets Microsoft Exchange servers exploiting the recently disclosed ProxyShell vulnerabilities.

A new ransomware gang named LockFile targets Microsoft Exchange servers using the recently disclosed ProxyShell vulnerabilities. The popular security expert Kevin Beaumont was one of the first researchers to report that the LockFile operators are using the Microsoft Exchange ProxyShell and the Windows PetitPotam vulnerabilities to take over Windows domains.

ProxyShell is the name of three vulnerabilities that could be chained by an unauthenticated remote attacker to gain code execution on Microsoft Exchange servers.

The three vulnerabilities used in ProxyShell attacks are:

  • CVE-2021-34473 – Pre-auth Path Confusion leads to ACL Bypass (Patched in April by KB5001779)
  • CVE-2021-34523 – Elevation of Privilege on Exchange PowerShell Backend (Patched in April by KB5001779)
  • CVE-2021-31207 – Post-auth Arbitrary-File-Write leads to RCE (Patched in May by KB5003435)

The vulnerabilities are exploited remotely through Microsoft Exchange’s Client Access Service (CAS) running on port 443 in IIS.

The vulnerabilities were discovered by security Researcher Tsai orange from Devcore, the issues were awarded $ 200,000 during the April 2021 Pwn2Own hacking contest. On Thursday, Orange Tsai gave a talk at the Black Hat conference and shared details about the Microsoft Exchange vulnerabilities.

Tsai explained that the ProxyShell attack chain targets multiple components in the Microsoft Exchange, including the Autodiscover service which is used by client applications to configure itself with minimal user input.

Threat actors started actively scanning for the Microsoft Exchange ProxyShell remote code execution flaws after researchers released technical details at the Black Hat hacking conference.

Threat actors first compromise a Microsoft Exchange server, then exploit the flaws to drop web shells that could be used to install and execute other malicious payloads.

After exploiting an Exchange server, the threat actors dropped web shells that could be used to upload other programs and execute them.

Security experts from Symantec reported that Lockfile gang first compromise the Microsoft Exchange servers then uses the PetitPotam vulnerability to take over a domain controller.

“The LockFile ransomware was first observed on the network of a U.S. financial organization on July 20, 2021, with its latest activity seen as recently as August 20. LockFile has been seen on organizations around the world, with most of its victims based in the U.S. and Asia.” states Symantec. “Indications are that the attackers gain access to victims’ networks via Microsoft Exchange Servers, and then use the incompletely patched PetitPotam vulnerability to gain access to the domain controller, and then spread across the network. It is not clear how the attackers gain initial access to the Microsoft Exchange Servers.”

The victims of the Lockfile ransomware gang are in the manufacturing, financial services, engineering, legal, business services, and travel and tourism sectors.

The ransom note used by the Lockfile gang is similar to the one used by the LockBit ransomware operators and reference the Conti gang in the email address used (contact@contipauper[.]com).

LockFile ransomware

Once encrypted the files, the ransomware will append the .lockfile extension to the encrypted file’s names.

In order to mitigate the exposure to the LockFile infections, admins should install the security updates that address Microsoft Exchange ProxyShell vulnerabilities and the Windows PetitPotam NTLM Relay vulnerability.

Experts pointed out that the Windows PetitPotam flaws only received incomplete updates anyway an unofficial patch was released by 0patch.

New PetitPotam micropatches have just been released, addressing additional known attack vectors that both our first micropatch and Windows Update did not address. With August 2021 Windows Updates installed and 0patch in place, PetitPotam should not work anymore.

— 0patch (@0patch) August 19, 2021

Follow me on Twitter: @securityaffairs and Facebook

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

Pierluigi Paganini

(SecurityAffairs – hacking, Lockfile ransomware)

[adrotate banner=”5″]

[adrotate banner=”13″]


facebook linkedin twitter

Cybercrime Hacking hacking news information security news IT Information Security LockFile ransomware malware PetitPotam Pierluigi Paganini ProxyShell Security Affairs Security News

you might also like

Pierluigi Paganini September 22, 2025
Stellantis probes data breach linked to third-party provider
Read more
Pierluigi Paganini September 22, 2025
FBI alerts public to spoofed IC3 site used in fraud schemes
Read more

leave a comment

newsletter

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

    recent articles

    Stellantis probes data breach linked to third-party provider

    Data Breach / September 22, 2025

    FBI alerts public to spoofed IC3 site used in fraud schemes

    Cyber Crime / September 22, 2025

    EU agency ENISA says ransomware attack behind airport disruptions

    Security / September 22, 2025

    Researchers expose MalTerminal, an LLM-enabled malware pioneer

    Malware / September 22, 2025

    Beware: GitHub repos distributing Atomic Infostealer on macOS

    Malware / September 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