The Qilin ransomware group has introduced a new variant, Qilin.B, which exhibits enhanced encryption methods and evasion techniques aimed at complicating detection and recovery. Tracked by cybersecurity firm Halcyon, this upgraded version now supports AES-256-CTR encryption for systems with AESNI hardware capabilities and retains ChaCha20 encryption for systems lacking such support. Furthermore, Qilin.B employs RSA-4096 with OAEP padding to secure encryption keys, making file decryption virtually impossible without access to the attacker’s private key or seed values, thus intensifying the challenges faced by victims in decrypting their files.
Initially identified by the cybersecurity community in mid-2022 under the alias Agenda, the Qilin ransomware has evolved significantly, moving from Golang to the more versatile Rust programming language. This shift has enabled the group to develop a more complex and resilient ransomware-as-a-service (RaaS) platform. In this model, Qilin affiliates reportedly receive between 80% to 85% of each ransom payment, adding financial motivation for cybercriminals to distribute the ransomware. With this RaaS infrastructure, Qilin has continued to attract affiliates while expanding its reach and attack sophistication.
Qilin.B also brings new operational tactics to avoid detection and disrupt recovery processes. In addition to encrypting data, it actively resists security analysis by terminating services associated with antivirus software, wiping Windows Event Logs, and deleting itself to cover its tracks. The variant also disables or kills processes tied to backup solutions, such as Veeam, as well as virtualization services like SQL and SAP, further complicating any restoration efforts. By deleting volume shadow copies, Qilin.B obstructs traditional methods of data recovery, increasing the pressure on victims to pay ransoms for decryption.
The rise of Qilin.B reflects broader trends in ransomware, where groups continuously enhance technical capabilities to maximize impact. With Qilin.B’s dual encryption options, anti-detection features, and focus on disabling backup systems, it exemplifies a shift toward more sophisticated and persistent threats in the ransomware landscape. The emergence of this variant underlines the urgent need for organizations to strengthen endpoint defenses, enhance data backup strategies, and adopt proactive threat detection measures to guard against the increasingly dangerous ransomware threat.
