Two experts get into why Lazarus exploiting a Windows zero-day is particularly concerning despite the vulnerability’s “Important” CVSS rating. And how kernel-level rootkits like FudModule can undermine the security tools defenders rely on, and what organizations can do when patching or traditional mitigations aren’t immediately possible.
John Strand, Owner, Black Hills Information Security (https://www.linkedin.com/in/john-strand-a1b4b62)
“This story highlights an important shift in how organizations need to think about defense. Effective cybersecurity can no longer be reduced to firewall rule changes, patching, and configuration updates. Those remain important, but they’re no longer sufficient on their own.
“Security teams need to start training for the moments when those traditional options aren’t available. What happens when a critical system can’t be patched? What happens when operational requirements prevent you from making firewall changes? Those situations are becoming increasingly common, especially in legacy environments and critical infrastructure.
“That’s where compensating controls become essential. Organizations should be regularly exercising these scenarios and asking, ‘What can we do today to reduce risk while we wait for a patch or a permanent fix?’ Whether it’s increased monitoring, network segmentation, deception technologies, stricter access controls, or enhanced threat hunting, teams need to understand which defensive options are available and when to deploy them.
“The goal of compensating controls isn’t to eliminate the risk. It’s to buy time. As zero-day vulnerabilities continue to emerge at a faster pace, organizations need strategies that slow attackers down and reduce their opportunities while vendors develop patches and defenders work to implement them.
“The organizations that will be most successful over the next several years won’t necessarily be the ones that patch the fastest. They’ll be the ones that have rehearsed how to operate safely when patching isn’t immediately possible.”
Denis Calderone, CTO, Suzu Labs (https://www.linkedin.com/in/deniscalderone)
“Lazarus has now exploited use-after-free vulnerabilities in Windows built-in drivers three times in two years to deploy the same rootkit. They went from appid.sys to AFD.sys to AFD.sys again. For a while, the standard playbook for getting kernel access was bring-your-own-vulnerable-driver: load a signed but buggy third-party driver, exploit it, get kernel privileges. Defenders adapted with driver allowlisting. Lazarus adapted by finding bugs in drivers that Windows ships by default. AFD.sys handles every socket operation on every Windows machine. You can’t blocklist it.
“Once the use-after-free fires, the attacker gets a kernel read/write primitive, and from there FudModule takes over. This is a rootkit that disables EDR callbacks, zeros out ETW provider registrations, and hides its own processes from the tools security teams rely on. The latest version, v3.1, adds the ability to tamper with Smart App Control, which means the rootkit is evolving faster than the mitigations Microsoft is building around it. And this CVE carries a CVSS 7.0, rated Important. There are 42 Critical patches in the same August Patch Tuesday release. If your vulnerability management program triages by severity score, this one is going to land in the middle of the queue behind remote code execution bugs that nobody has actually exploited yet. That’s exactly backwards.
“CISA added CVE-2026-68820 to the Known Exploited Vulnerabilities catalog on August 11 with a federal remediation deadline of August 25, so needless to say, get this one patched right away, regardless of the CVSS score. Given that Lazarus had at least five weeks of active exploitation before the fix shipped, organizations in defense, aerospace, and adjacent sectors should be particularly diligent and treat anything unpatched since early July as potentially compromised. Check Point’s report includes the full IOC list covering file hashes, C2 domains, and the specific malware components used in the campaigns. Hunt for evidence of the MISTPEN downloader. It beacons out using Microsoft Graph API and OneDrive traffic, so look for anomalous indicators from workstations that don’t typically use those tools. Also look for unsigned DLLs loaded alongside legitimate PDF viewers and any evidence of ETW provider or kernel callback manipulation. Lazarus has shown that it’s possible to render EDR telemetry useless from the kernel level, and too many defenders still treat their EDR as a single source of truth. That dependency is exactly what FudModule is built to exploit.”
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This entry was posted on August 14, 2026 at 8:00 am and is filed under Commentary with tags Microsoft. You can follow any responses to this entry through the RSS 2.0 feed.
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What the latest Lazarus attack says about the limits of EDR
Two experts get into why Lazarus exploiting a Windows zero-day is particularly concerning despite the vulnerability’s “Important” CVSS rating. And how kernel-level rootkits like FudModule can undermine the security tools defenders rely on, and what organizations can do when patching or traditional mitigations aren’t immediately possible.
John Strand, Owner, Black Hills Information Security (https://www.linkedin.com/in/john-strand-a1b4b62)
“This story highlights an important shift in how organizations need to think about defense. Effective cybersecurity can no longer be reduced to firewall rule changes, patching, and configuration updates. Those remain important, but they’re no longer sufficient on their own.
“Security teams need to start training for the moments when those traditional options aren’t available. What happens when a critical system can’t be patched? What happens when operational requirements prevent you from making firewall changes? Those situations are becoming increasingly common, especially in legacy environments and critical infrastructure.
“That’s where compensating controls become essential. Organizations should be regularly exercising these scenarios and asking, ‘What can we do today to reduce risk while we wait for a patch or a permanent fix?’ Whether it’s increased monitoring, network segmentation, deception technologies, stricter access controls, or enhanced threat hunting, teams need to understand which defensive options are available and when to deploy them.
“The goal of compensating controls isn’t to eliminate the risk. It’s to buy time. As zero-day vulnerabilities continue to emerge at a faster pace, organizations need strategies that slow attackers down and reduce their opportunities while vendors develop patches and defenders work to implement them.
“The organizations that will be most successful over the next several years won’t necessarily be the ones that patch the fastest. They’ll be the ones that have rehearsed how to operate safely when patching isn’t immediately possible.”
Denis Calderone, CTO, Suzu Labs (https://www.linkedin.com/in/deniscalderone)
“Lazarus has now exploited use-after-free vulnerabilities in Windows built-in drivers three times in two years to deploy the same rootkit. They went from appid.sys to AFD.sys to AFD.sys again. For a while, the standard playbook for getting kernel access was bring-your-own-vulnerable-driver: load a signed but buggy third-party driver, exploit it, get kernel privileges. Defenders adapted with driver allowlisting. Lazarus adapted by finding bugs in drivers that Windows ships by default. AFD.sys handles every socket operation on every Windows machine. You can’t blocklist it.
“Once the use-after-free fires, the attacker gets a kernel read/write primitive, and from there FudModule takes over. This is a rootkit that disables EDR callbacks, zeros out ETW provider registrations, and hides its own processes from the tools security teams rely on. The latest version, v3.1, adds the ability to tamper with Smart App Control, which means the rootkit is evolving faster than the mitigations Microsoft is building around it. And this CVE carries a CVSS 7.0, rated Important. There are 42 Critical patches in the same August Patch Tuesday release. If your vulnerability management program triages by severity score, this one is going to land in the middle of the queue behind remote code execution bugs that nobody has actually exploited yet. That’s exactly backwards.
“CISA added CVE-2026-68820 to the Known Exploited Vulnerabilities catalog on August 11 with a federal remediation deadline of August 25, so needless to say, get this one patched right away, regardless of the CVSS score. Given that Lazarus had at least five weeks of active exploitation before the fix shipped, organizations in defense, aerospace, and adjacent sectors should be particularly diligent and treat anything unpatched since early July as potentially compromised. Check Point’s report includes the full IOC list covering file hashes, C2 domains, and the specific malware components used in the campaigns. Hunt for evidence of the MISTPEN downloader. It beacons out using Microsoft Graph API and OneDrive traffic, so look for anomalous indicators from workstations that don’t typically use those tools. Also look for unsigned DLLs loaded alongside legitimate PDF viewers and any evidence of ETW provider or kernel callback manipulation. Lazarus has shown that it’s possible to render EDR telemetry useless from the kernel level, and too many defenders still treat their EDR as a single source of truth. That dependency is exactly what FudModule is built to exploit.”
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This entry was posted on August 14, 2026 at 8:00 am and is filed under Commentary with tags Microsoft. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.