Ransomware encrypts or steals data to disrupt operations and extort victims, making backups, access controls, and incident response essential.
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Background for this topic.
Ransomware is malware used to deny access to systems or data, usually by encrypting files and demanding payment for decryption. Many operations also steal sensitive information and threaten to publish it, so an attack can create both an availability crisis and a privacy or disclosure risk. Initial access may involve phishing, stolen credentials, exposed remote services, or exploitation of unpatched vulnerabilities; attackers may then move through the network before deploying the payload.
Defenses should combine vulnerability management, phishing-resistant authentication where practical, endpoint and network monitoring, and backups that are isolated from routine administrator access and regularly tested for recovery. Organizations should also limit privileges and segment critical systems to reduce the blast radius. An incident requires rapid containment, preservation of forensic evidence, restoration from known-good backups, and assessment of notification, legal, and regulatory obligations. Threat intelligence can help identify relevant criminal infrastructure or tactics, but it does not replace sound access control, patching, detection, and recovery practices.
Tens of thousands of Patelco customers remain without access to their accounts, with no estimates for when systems will be restored.
Attackers clear logs before exploitation and use "no caller ID" numbers to negotiate ransoms, complicating detection and forensics efforts.
The highest ransom demanded by threat actors this year so far was nearly 20 times last year's average.
The cyberattack disrupted national laboratory services, which could slow response to disease outbreaks such as mpox, experts warn.
A ransomware attack has become a supply chain issue, thanks to the victim's partnerships with other financial services companies.