• 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

U.S. CISA adds Cisco ISE and PaperCut NG/MF flaws to its Known Exploited Vulnerabilities catalog

 | 

Critical WordPress Post SMTP plugin flaw exposes 200K+ sites to full takeover

 | 

Scattered Spider targets VMware ESXi in using social engineering

 | 

China-linked group Fire Ant exploits VMware and F5 flaws since early 2025

 | 

Allianz Life data breach exposed the data of most of its 1.4M customers

 | 

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

 | 
  • 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
  • Bitdefender released a decryptor for the ShrinkLocker ransomware

Bitdefender released a decryptor for the ShrinkLocker ransomware

Pierluigi Paganini November 14, 2024

Bitdefender released a decryptor for the ShrinkLocker ransomware, which modifies BitLocker configurations to encrypt a system’s drives.

ShrinkLocker ransomware was first discovered in May 2024 by researchers from Kaspersky. Unlike modern ransomware it doesn’t rely on sophisticated encryption algorithms and modifies BitLocker configurations to encrypt a system’s drives.

It first checks if BitLocker is enabled and, if not, installs it. Then, it re-encrypts the system using a randomly generated password. This unique password is uploaded to a server controlled by the attacker.

The malware then disables default protections to prevent accidental encryption and uses the ‘-UsedSpaceOnly’ flag for faster encryption of only occupied disk space. The random password is generated from network traffic and memory data, making brute-forcing difficult. ShrinkLocker also deletes and reconfigures BitLocker protectors, complicating the recovery of encryption keys.

After the system reboots, the user is prompted to enter the password to unlock the encrypted drive. The attacker’s contact email is displayed on the BitLocker screen, directing victims to pay a ransom for the decryption key. 

“The attacker’s email is displayed, demanding a ransom for the decryption key. Using Group Policy Objects (GPOs) and scheduled tasks, the ransomware can encrypt multiple systems in a network in as little as 10 minutes per device, allowing for a quick, widespread compromise of a domain.” reads the post published by Bitdefender. “This simplicity makes it appealing to individual threat actors, even those not part of larger ransomware-as-a-service (RaaS) operations.”

Bitdefender researchers speculate the ransomware borrows the code from a benign application written more than ten years ago.

The code is simple enough that even less experienced attackers could use it. However, the investigation revealed positive news: it’s possible to develop a decryptor and configure BitLocker to mitigate such attacks.

Bitdefender observed an attack on a healthcare organization, where threat actors encrypted Windows 10, Windows 11, and Windows Server devices, including backups. The encryption process took just 2.5 hours, causing the organization to lose access to critical systems and potentially hindering patient care.

Bitdefender has released a free decryption tool to help victims recover their files.

“However, in the case of ShrinkLocker, we’ve identified a specific window of opportunity for data recovery immediately after the removal of protectors from BitLocker-encrypted disks.” reads the post published by Bitdefender. “We decided to make this decryptor publicly available, adding to our collection of 32 previously released decryption tools.”

The decryption process may take time depending on victim’s system’s hardware and the encryption’s complexity. Once complete, the decryptor will automatically unlock the drive and disable smart card authentication.

Proactive monitoring of Windows event logs, specifically from the “Microsoft-Windows-BitLocker-API/Management” source, can help organizations detect early stages of BitLocker attacks, such as when attackers test encryption capabilities. Monitoring events with IDs 776 (protector removal) and 773 (suspension) can be particularly useful.

Additionally, configuring Group Policy to store BitLocker recovery information in Active Directory Domain Services (AD DS) and enforcing the policy “Do not enable BitLocker until recovery information is stored to AD DS for operating system drives” can prevent unauthorized encryption. This policy ensures BitLocker can’t be enabled without the recovery information being securely stored, reducing the risk of BitLocker-based attacks.

“ShrinkLocker is a novel ransomware strain that leverages a unique approach to encrypt systems. By exploiting BitLocker, a legitimate Windows feature, it can rapidly encrypt entire drives, including system drives.” concludes the report.

Follow me on Twitter: @securityaffairs and Facebook and Mastodon

Pierluigi Paganini

(SecurityAffairs – hacking, iPhones)


facebook linkedin twitter

Hacking hacking news information security news IT Information Security Pierluigi Paganini Security News ShrinkLocker ransomware

you might also like

Pierluigi Paganini July 28, 2025
U.S. CISA adds Cisco ISE and PaperCut NG/MF flaws to its Known Exploited Vulnerabilities catalog
Read more
Pierluigi Paganini July 28, 2025
Critical WordPress Post SMTP plugin flaw exposes 200K+ sites to full takeover
Read more

leave a comment

newsletter

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

    recent articles

    U.S. CISA adds Cisco ISE and PaperCut NG/MF flaws to its Known Exploited Vulnerabilities catalog

    Security / July 28, 2025

    Critical WordPress Post SMTP plugin flaw exposes 200K+ sites to full takeover

    Security / July 28, 2025

    Scattered Spider targets VMware ESXi in using social engineering

    Cyber Crime / July 28, 2025

    China-linked group Fire Ant exploits VMware and F5 flaws since early 2025

    Hacking / July 28, 2025

    Allianz Life data breach exposed the data of most of its 1.4M customers

    Data Breach / July 27, 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