LockBit5 ransomware group lists prommgroup.com on its leak site

• Ransomware group: LockBit5
• Country: Russia
• Sector: Professional Services
• Announcement date: December 26, 2025

LockBit5 claims data breach against prommgroup.com

The LockBit5 ransomware group has officially listed prommgroup.com on its dedicated leak site, alleging that the organization has been the victim of a data breach. This announcement, made on December 26, 2025, follows a claimed attack date of December 6, 2025. By listing the organization on its platform, the threat actor is utilizing public exposure as a tool for extortion, a common tactic used by modern ransomware operations to pressure victims into meeting financial demands.

The listing appeared on the group's leak site, which serves as a public bulletin for victims who refuse to pay ransoms. In such scenarios, the group typically provides a countdown timer to create a sense of urgency, signaling to the public and the victim that the stolen data will be published if specific conditions are not met. This method of psychological pressure is a cornerstone of contemporary cyber extortion campaigns.

Details of the alleged incident

According to the information provided by the LockBit5 group, the organization was targeted in an attack that reportedly occurred in early December. The group's announcement included various details regarding the background and operations of the targeted company. However, the specific nature of the data that has been allegedly compromised remains unknown. The listing does not specify the types of files, the volume of data, or the specific contents that the group claims to have exfiltrated.

The listing names no data types.

About Promm group

Promm Group is a professional services firm based in Thailand. The company provides a variety of services including real estate development, investment, and management. Originally established under the name Prommaharaj Land Development, the firm has expanded its operations to manage diverse commercial and residential projects across the region.

Analysis and implications of the threat

This incident can be interpreted as an attempt by the LockBit5 group to exert pressure on the organization using double-extortion tactics. In a double-extortion scheme, attackers not only encrypt the victim's systems but also steal sensitive information, threatening to leak it publicly to maximize leverage. Until the actual content of the leaked data is clarified, it must be assumed that sensitive information, such as trade secrets or customer data, could be at risk.

The implications of such a breach are multifaceted. For an organization operating in the professional services sector, a data leak can lead to significant reputational damage and a loss of trust among stakeholders. Furthermore, the exposure of internal data can increase the risk of targeted phishing attacks against the organization's customers and business partners, as attackers may use stolen information to craft highly convincing social engineering campaigns.

From a regulatory perspective, the organization's location and the nature of the incident may trigger legal processes regarding local data protection regulations. Organizations facing such threats should prioritize incident response protocols, including forensic investigation to determine the scope of the breach and enhanced monitoring to detect further unauthorized activity. Strengthening defensive measures, such as multi-factor authentication and rigorous access controls, remains a critical component of a robust cybersecurity posture.

LockBit is a known Ransomware-as-a-Service (RaaS) group that has been tracked since 2019. It is notable that the group has returned with a new version of its malware following the disruption of its infrastructure in February 2024, demonstrating the resilience and evolution of such threat actor groups in the current cyber threat landscape.