Summary South Korean Wiper Malware Attack & Defensive Measures

Reporting and technical details surrounding the malware used in the March 20, 2013, attack on South Korean assets have been varied and inconsistent. However, there are some commonalities reported across multiple organizations that provide some level of insight into the malware, dubbed DarkSeoul.
The common attributes of the attack campaign are the following:

• The malicious file wipes the master boot record (MBR) and other files.
•  The malware was hard coded with a specific execution date and time and searches machines for credentials with administrative/root access to servers.
•  The malware is written to specifically target South Korean victims.
•  The attack is effective on multiple operating systems.
• The design is low sophistication – high damage.

When assessing the potential risk to U.S. Critical Infrastructure and Key Resources (CIKR), it is important to understand that DarkSeoul appears to have been coded for a specific target in this case and designed to evade typical South Korean antivirus processes. As this malware is currently packaged, it is a low risk to U.S. CIKR, however, the concepts underpinning this attack would likely succeed in many common enterprise environments. For this reason, U.S. CIKR owners and operators should continue the best standard security practices to avoid infection and propagation of a wiper or other type of malware that may impact their systems.
Defensive Measures
Based on the common attributes detailed above, US‐CERT reminds users and administrators of the importance of best practices to strengthen the security posture of their organization's systems.
CIKR owners and operators should work toward a resilient network model that assumes such an attack will occur against their enterprise. The goal is to minimize damage, and provide pathwaysfor restoration of critical business functions in the shortest amount of time possible.

• Encourage users to transfer critical files to network shares, to allow for centralized backups. Leverage technical solutions to automate centralized storage where possible to reduce reliance on end-user voluntary compliance Execute daily backups of all critical systems, including offline and offsite copies of backup media.
• Periodically execute a practice data restoration from backups, including key databases to ensure integrity of existing backups and processes.
• Establish emergency communications plans should network resources become unavailable.
• Isolate any critical networks (including operations networks) from business systems, and where possible segment the business networks.
• Identify critical systems and evaluate the need to have on-hand spares to quickly restore service.
• Recognize that without proper internal monitoring, an organization’s “Enterprise Trust