Qakbot: Understand how Ransomware works

Ransomware has become one of the most dangerous cybersecurity threats facing organizations and individuals today.

This form of malware encrypts files and systems, demanding payment to restore access. One of the most prolific strains is Qakbot (also known as Qbot or Pinkslipbot). Active since 2007, it has infected hundreds of thousands of systems globally through evolving infection vectors and capabilities.

This article will provide a comprehensive overview of how the Qakbot ransomware operates, its key capabilities, the impact of an attack, and steps organizations can take to defend against it.

How Qakbot Infects Systems

Qakbot utilizes multiple infection vectors to gain access and spread through systems and networks.

The most common method is through phishing emails containing malicious attachments or links. The emails are carefully crafted to appear legitimate, often impersonating trusted sources or containing information personalized to the recipient.

If the user clicks the link or enables the embedded content, malware is downloaded, providing an initial foothold into the system.

Qakbot malware has also been spread through compromised websites, drive-by downloads, and brute force attacks on external services like Remote Desktop Protocol. Once executed, the malware installs various components and modules that allow the ransomware payload to be downloaded.

This includes a credential stealer for lateral movement and tools to evade detection, like disabling security software.

The initial infection will establish communication with the command and control servers operated by the cybercriminals behind Qakbot.

These servers can remotely instruct infected machines to download additional modules, spread laterally using stolen credentials, and ultimately deploy the ransomware payload. This modular architecture allows the malware’s capabilities to expand over time continually.

Qakbot Capabilities

Qakbot possesses multiple modules that provide a wide range of malicious functionality:

• Keylogging and credential theft – The malware stealthily records keystrokes, capturing usernames, passwords, and other sensitive data users enter. This enables lateral movement throughout the network.
• Lateral movement – By stealing credentials from compromised machines, Qakbot can spread to other systems via tools like PsExec, SMB, and WMI. This expands the footprint of machines it can infect.
• Data exfiltration – Before deploying ransomware, Qakbot will extract files and data from the network for extortion and resale on dark web markets.
• Ransomware encryption – The ransomware module recursively encrypts files across local drives and shared network volumes with strong AES encryption. Most file types can be encrypted.
• Ransom notes – After encrypting files, Qakbot displays ransom notes demanding payment in Bitcoin to receive a decryption key. Partial decryption may be offered as “proof.”
• Threats of data leaks – Qakbot threatens to publish exfiltrated data if the ransom is not paid, applying additional pressure on victims.

This multi-pronged approach allows Qakbot to infiltrate systems, entrench itself in the network, steal valuable data, and then deploy file-encrypting ransomware in a coordinated attack.

The Ransom Demand

The ransom demand itself is delivered by displaying ransom notes on the infected system's screens. The notes will include payment instructions, the ransom amount, and threats regarding stolen data.

Demands usually range from .5 to 2 Bitcoins, although larger organizations may see higher amounts.

Payment is demanded through cryptocurrencies like Bitcoin or Monero to preserve the criminals' anonymity. The notes provide a Bitcoin wallet address to send payment and a unique ID number for the victim.

Once paid, the criminals promise to provide the decryption software. Partial decryption may be performed first as proof.

However, even if paid in full, there is no guarantee files will be recovered. The criminals may simply take the money without providing working decryption keys. Qakbot also threatens to publish any stolen data from victims who refuse to pay up, further incentivizing payment.

Impact of Infection

A Qakbot infection can severely impact affected individuals and organizations. Encrypting crucial files essentially locks staff out of critical systems and data.

This brings business operations and productivity to a halt. Even if a ransom is paid, downtime and costs due to disrupted operations can persist.

If not properly segmented, Qakbot can spread quickly on a network by leveraging stolen credentials.

This can rapidly escalate the scale of encryption and the machines impacted. Entire file servers may be encrypted, affecting shared resources. Data exfiltrated before encryption may also be published or sold online.

Even after the attack, considerable time and resources are required to restore systems and revoke compromised credentials fully.

Stolen credentials may be used for future attacks as well. Extensive costs also arise from emergency response, network monitoring, and implementing additional defenses.

Protection and Recovery Recommendations

Qakbot exploits security gaps, so organizations should implement layered defenses to reduce the risk of infection and disrupt attacks in progress:

• User education – Train staff to identify and avoid phishing attempts and enable malicious files. Do not open attachments from unknown sources.
• Patching – Maintain up-to-date patching on operating systems, software, and firmware to eliminate vulnerabilities.
• Authentication – Require strong, unique passwords and enable multi-factor authentication wherever possible. Limit the use of shared admin credentials.
• Restrict execution – Use application whitelisting and controls like PowerShell Constrained Language Mode. Limit software allowed to run.
• Segment networks – Isolate and firewall critical systems to restrict lateral movement. Avoid exposing SMB and RDP externally.
• Monitor systems – Inspect network traffic and endpoint behavior for signs of C2 callbacks, lateral activity, and ransomware.
• Backups – Maintain recent backups offline and regularly test backup and restoration to rebuild systems quickly.

If Qakbot evades defenses and encrypts systems, recovery options include:

• Decryption – In some cases, decryption may be possible through tools like those offered by NoMoreRansom.org. This depends on the strain and encryption methods.
• Ransom payment – This is not recommended as it encourages more attacks and does not guarantee file recovery. Consult law enforcement first.
• Rebuild systems – Completely rebuild infected systems from scratch and restore data from offline, read-only backups made before infection.
• Account lockouts – To contain lateral movement, block Active Directory and cloud application accounts that may have been compromised. Require password resets.

Prevention is more effective than reacting post-infection. By layering robust defenses and preparing secure backups, organizations can reduce the likelihood of a Qakbot incursion and the impacts if one succeeds.

Ongoing user education and testing response plans are also essential.

Conclusion

Qakbot has emerged as one of the most versatile and destructive ransomware strains impacting businesses and organizations globally in recent years.

Its layered infection process enables widespread encryption of systems and data. By understanding Qakbot's capabilities and modern defense strategies, potential victims can harden their infrastructure against attacks and implement the backups and response plans required for quick recovery should an incursion occur.

With ransomware attacks on the rise, proactive measures are essential to defend against the disruption Qakbot and similar threats pose.

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