This week, the Yanluowang ransomware gang published Walmart as a victim on their leak site, stating they had encrypted 40-50 thousand devices. The group claimed the attack took place over a month ago and Walmart never responded to their ransom demands of $55 million. The group also posted files that appear to be from Walmart’s internal network. Walmart has publicly denied that the attack took place and stated that they monitor systems 24/7 and believe the claim by the Yanluowang gang to be inaccurate. This would not be the first time a ransom group lied about a successful attack of a major corporation to gain notoriety.
Regardless of whether they decide to pay a ransom or not, organizations that are victims of ransomware attacks should seek professional help from incident response and data recovery service providers and consider reporting the incident to law enforcement.
To protect against ransomware attacks, organizations should:
- Regularly back up data, air gap, and password protect backup copies offline.
- Ensure copies of critical data are not accessible for modification or deletion from the system where the data resides.
- Implement network segmentation.
- Implement a recovery plan to maintain and retain multiple copies of sensitive or proprietary data and servers in a physically separate, segmented, secure location (i.e., hard drive, storage device, the cloud).
- Install updates/patch operating systems, software, and firmware as soon as practical after they are released.
- Implement monitoring of security events on employee workstations and servers, with a 24/7 Security Operations Center to detect threats and respond quickly.
- Use multifactor authentication where possible.
- Use strong passwords and regularly change passwords to network systems and accounts, implementing the shortest acceptable timeframe for password changes.
- Avoid reusing passwords for multiple accounts.
- Focus on cyber security awareness and training.
- Regularly provide users with training on information security principles and techniques as well as overall emerging cybersecurity risks and vulnerabilities.