CVE-2022-44698: Microsoft Defender SmartScreen Security Feature Bypass Vulnerability

CVE-2022-44698 is a security feature bypass in Microsoft Defender SmartScreen. It lets an attacker evade Mark of the Web (MOTW) protections by using a specially crafted malicious file. Because MOTW is a common Windows defense that flags files from the internet and triggers extra scrutiny, a bypass can reduce the chance that users or automated controls will block or warn about untrusted content. CISA notes known ransomware use of this vulnerability, so organizations that rely on SmartScreen and MOTW should treat it as a priority for inventory and remediation.

Public detail is limited to the CISA summary and the CWE classification; exact affected builds, scoring, and exploit mechanics must be confirmed against the Microsoft vendor advisory. The required action is to apply updates per vendor instructions.

How it works

The weakness is classified as CWE-755 (Improper Handling of Exceptional Conditions). In this class of flaw, the product does not correctly handle an unexpected or crafted condition, allowing security logic to be skipped or weakened. Here, SmartScreen’s MOTW-related checks can be bypassed when the attacker supplies a specially crafted malicious file. An attacker who can deliver such a file (for example via download, email attachment, or other user-initiated transfer) may cause the system to treat the file without the full MOTW protections that would otherwise apply. The result is reduced visibility and fewer automatic blocks or prompts that defenders normally rely on. No further exploit mechanics are provided in the available facts; treat any public proof-of-concept claims cautiously and validate against the vendor advisory.

Am I affected? How to find it in your systems

Microsoft Defender SmartScreen is a Windows component commonly present on client and some server endpoints that use Microsoft Defender. It participates in MOTW handling for files originating from the internet or other untrusted zones. Inventory all Windows systems that have Microsoft Defender enabled and that process user-downloaded or externally sourced files.

• Enumerate endpoints via your asset or EDR inventory; confirm Microsoft Defender / SmartScreen is present and active.
• Check the installed Defender and Windows update level against the versions listed in the Microsoft advisory for CVE-2022-44698; do not assume a version range without confirming the advisory.
• Review configurations that rely on MOTW (for example, Office Protected View, Windows attachment handling, or browser download policies) to understand residual risk if the bypass is present.
• For exploitation signs, look for unusual file execution or process creation involving recently downloaded files that lack expected MOTW-related blocks or warnings; correlate with EDR telemetry for SmartScreen or MOTW events. Specific log signatures are not detailed in the facts, so baseline normal SmartScreen activity and investigate anomalies.

How to remediate

Patch first. Apply the Microsoft updates that address CVE-2022-44698 exactly as directed in the vendor advisory. CISA’s required action is to apply updates per vendor instructions; follow Microsoft’s guidance for deployment order, reboots, and verification.

• After patching, confirm the update is installed and that SmartScreen / MOTW behavior matches the post-fix expectations described by the vendor.
• For this class of bypass, also review and harden MOTW-dependent controls: ensure Office Protected View, browser download protections, and attachment scanning remain enabled where appropriate.
• Limit the ability of untrusted files to execute without review (application control, least privilege, and controlled folder or script restrictions help reduce impact even if MOTW is bypassed).
• Retest detection rules that previously relied on MOTW presence so they do not silently fail after the change.

If you can't patch immediately

Until the vendor update can be applied, reduce exposure with compensating controls that do not depend solely on SmartScreen MOTW checks.

• Segment high-risk user workstations and restrict outbound file-sharing or download paths where practical.
• Use application allow-listing or script control so that newly arrived files cannot run freely even if MOTW is missing.
• If you operate a network or host-based filter capable of virtual patching, block or quarantine the file patterns or delivery vectors associated with this bypass once Microsoft or your security vendor publishes indicators; confirm any signatures against current guidance.
• Temporarily tighten download and email attachment policies (sandboxing, forced scanning, or blocking high-risk extensions) and increase monitoring for execution of files that originated from the internet.
• Disable or restrict non-essential features that process untrusted files if your environment allows it, and document the temporary change for later reversal after patching.

If your data may have been exposed

Actively exploited vulnerabilities, including those with known ransomware use, can lead to compromise and data exposure. If you suspect exploitation, isolate affected hosts, preserve forensic evidence, and follow your incident-response process. You can also run a free exposure scan of your email addresses against known breach data to check whether credentials or personal information have already appeared in public dumps, then force password resets and enable multi-factor authentication where accounts may be at risk.