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Sandbox escape in the Avast/AVG/Norton sandbox minifilter driver (aswSnx.sys) on Windows allows an authenticated, low-privileged process already executing inside the sandbox to break file isolation and escalate to SYSTEM (CVSS 8.8, AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H, CWE-281). The driver opens the virtualization target with only GENERIC_WRITE and FILE_WRITE_ATTRIBUTES, omitting WRITE_DAC, so every attempt to reapply the original DACL fails silently and virtualized copies of sensitive files are left with permissive permissions; the IRP_MJ_CREATE handler additionally fails to strip WRITE_DAC for sensitive directories, letting a sandboxed process rewrite the security descriptor of a virtualized object, read the virtualized SAM copy, extract local NTLM hashes and run code as SYSTEM. Publicly available exploit code exists (the PrettyPrague proof of concept), the vendor has released patches for the affected Avast, AVG and Norton products, and no CISA KEV entry indicates confirmed active exploitation.
Sandbox escape in the Avast/AVG/Norton sandbox minifilter driver (aswSnx.sys) on Windows allows an authenticated, low-privileged process already executing inside the sandbox to break file isolation and escalate to SYSTEM (CVSS 8.8, AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H, CWE-281). The driver opens the virtualization target with only GENERIC_WRITE and FILE_WRITE_ATTRIBUTES, omitting WRITE_DAC, so every attempt to reapply the original DACL fails silently and virtualized copies of sensitive files are left with permissive permissions; the IRP_MJ_CREATE handler additionally fails to strip WRITE_DAC for sensitive directories, letting a sandboxed process rewrite the security descriptor of a virtualized object, read the virtualized SAM copy, extract local NTLM hashes and run code as SYSTEM. Publicly available exploit code exists (the PrettyPrague proof of concept), the vendor has released patches for the affected Avast, AVG and Norton products, and no CISA KEV entry indicates confirmed active exploitation.