• SecureDisruptions

New Day for Zero-day Exploits: Microsoft Exchange mitigation

On the heels of a global wave of cyberattacks that exploit zero-day vulnerabilities in Microsoft Exchange, the software giant has released a one-click mitigation tool to protect Exchange Servers.


Cyberattacks exploiting four vulnerabilities targeted email systems of hundreds of thousands of organizations globally, including the European Banking Association and Norway’s parliament, the Storting, among other victims. Earlier this month, Microsoft attributed the attack to Chinese state-sponsored hacking group Hafnium.


Conditions required for exploitation of the zero-day include user accounts on the vulnerable system, according to Ilia Kolochenko, chief architect of ImmuniWeb, a Switzerland-based application security firm. Kolochenko raised questions involving the timing of the EBA intrusion and its detection.


Kolochenko said hardening systems and continuous monitoring for network anomalies could have prevented exploitation or enabled detection by the EBA in a timely manner if the intrusion occurred prior to public disclosure of the vulnerability. “If the intrusion had happened after the disclosure, but prior to the emergency patch, the vulnerable systems should have been immediately disconnected to prevent exploitation in the wild,” he said.


Dr. Oren Eytan, chief executive at content disarm and reconstruction platform Odix, said attackers expend “substantial efforts” on penetration of large enterprises and financial institutions. The wide distribution of Microsoft Exchange Servers globally, particularly at such institutions, makes them excellent targets for attackers.


The sizable amount of source code makes discovery of a vulnerability a relatively high likelihood for threat actors. Considering these factors, Eytan warned that the next attack is “only a question of time.”


Given the proliferation of supply chain attacks, how do you protect your organization? The recent attacks underscore the importance of timing and the risk recovery plan that affords the most resilience once the breach has occurred. What steps can leadership take to ensure the proper balance between prevention and recovery at their organizations?


Expertise: Cyber risks change and evolve regularly. An expert grasp of the latest data threats and how they might target your vulnerabilities can alert you to blind spots in your prevention and recovery strategies. Headcount dedicated to cyber expertise is an investment in the protection of your data, and of your reputation. Your shareholders, customers, and employees need to feel safe putting their personal information in your care. Embed this expertise in your org chart and recruitment/development plan.


Layered recovery plan: Data breaches can take three forms: data extraction, data corruption, and loss of access to data. To effectively construct a cybersecurity strategy, CEOs and boards need to require a business impact analysis wherein CISOs create scenarios for each of type of breach and document a plan to swiftly address each threat if it occurs. To be effective, roles and responsibilities need to be clearly defined, and the plan must include communications strategies and tactics for internal and external audiences. “Real time” is no time to be processing, addressing, and communicating the impact of a breach.


Continuous assessment: Cybersecurity is not a “set it and forget it” thing. As cyber risks change and increase, the plan will require stringent review, testing, and evaluating the ability of the entity to survive a breach. In large organizations, this involves cross-functional teams to ensure that potential impacts to various businesses, operations, and audiences are fully understood and accounted for. Clear metrics for successful recovery are essential to assessing the plan and the ROI.


Keeping up with cybersecurity may seem like a perpetual game of Whac-A-Mole but, like many cyber versions of older analog games, the player who is most adept at exploiting the latest version’s hacks and adding a few surprises has the best chance at winning.

Reporting by Carol McGall; editing by Jeremy Seth Davis.