Microsoft Scrambles to Thwart New Zero-Day Attacks

The zero-day attacks against Microsoft’s software products are showing no signs of slowing down.

For the second consecutive month, the world’s largest software maker rushed out patches to cover vulnerabilities that were already exploited as zero-days in the wild, including a pair of belated fixes for Microsoft Exchange Server security defects targeted by a state-sponsored threat actor for several months.

As part of its scheduled Patch Tuesday update process, Microsoft flagged six distinct vulnerabilities in the “exploitation detected” category and urged Windows administrators to treat these updates with utmost urgency.

Redmond’s security response team documented four new exploited zero-days — CVE-2022-41125, CVE-2022-41073, CVE-2022-41091 and CVE-2022-41128 — alongside two Exchange Server bugs (CVE-2022-41040 and CVE-2022-41082) and warned that exploits are swirling in privilege escalation, feature bypass and remote code execution attacks.

The four new zero-days affect the Windows CNG Key Isolation Service, the Windows Print Spooler, Windows Mark of the Web Security, and Windows Scripting Languages. 

[ READ: Microsoft Links Exchange Zero-Day Exploits to State-Sponsored Hackers ]

The two Exchange Server patches cover a remote code execution flaw and a privilege escalation bug that was part of an exploit chain used by what Microsoft described as a state-sponsored threat actor.

The existence of the Exchange Server vulnerabilities became public in late September, when Vietnamese cybersecurity company GTSC reported seeing two previously unknown Exchange flaws being exploited in August against critical infrastructure.  

Microsoft conducted its own analysis and determined that a single state-sponsored threat actor has exploited the zero-days in highly targeted attacks aimed at fewer than 10 organizations. 

The flaws are documented as a server-side request forgery (SSRF) issue that can be exploited for privilege escalation (CVE-2022-41040) and a remote code execution flaw when PowerShell is accessible to the attacker (CVE-2022-41082). 

[ READ: Microsoft: China Flaw Disclosure Law Part of Zero-Day Exploit Surge ]

The surge in zero-day exploits, especially those used by skilled hacking teams linked to governments, coincides with a one-year-old Chinese law that sets strict rules around giving the Chinese government an early heads-up on the existence of critical, exploitable software flaws.

Microsoft made a direct connection between the Chinese law and a noticeable surge in zero-day attacks against all major computer platforms over the last two years. 

So far this year, there have been at least 46 documented in-the-wild zero-day attacks against software products and mobile operating systems, with Microsoft atop the oft-targeted vendor list.

According to ZDI, a company that closely tracks security-themed software updates, Microsoft’s latest Patch Tuesday release covered at least 64 documented vulnerabilities affecting multiple Windows products and OS components.

Related: Microsoft: China Flaw Disclosure Law Part of Zero-Day Exploit Surge

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