cbcvebase.
CVE-2023-28252
published 2023-04-11

CVE-2023-28252: Windows Common Log File System Driver Elevation of Privilege Vulnerability

PriorityP188high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
KEVITWEXPLOITRansomware
CISA Known Exploited Vulnerabilitydue 2023-05-02
Exploited in the wild
EPSS
48.97%
98.8th percentile
Windows Common Log File System Driver Elevation of Privilege Vulnerability

Affected

41 ranges· showing 25
VendorProductVersion rangeFixed in
microsoftwindows_10_1507< 10.0.10240.1986910.0.10240.19869
microsoftwindows_10_1607< 10.0.14393.585010.0.14393.5850
microsoftwindows_10_1809< 10.0.17763.425210.0.17763.4252
microsoftwindows_10_20h2< 10.0.19042.284610.0.19042.2846
microsoftwindows_10_21h2< 10.0.19044.284610.0.19044.2846
microsoftwindows_10_22h2< 10.0.19045.284610.0.19045.2846
microsoftwindows_10_version_1507>= 10.0.10240.0 < 10.0.10240.1986910.0.10240.19869
microsoftwindows_10_version_1607>= 10.0.14393.0 < 10.0.14393.585010.0.14393.5850
microsoftwindows_10_version_1809>= 10.0.0 < 10.0.17763.425210.0.17763.4252
microsoftwindows_10_version_1809>= 10.0.17763.0 < 10.0.17763.425210.0.17763.4252
microsoftwindows_10_version_20h2>= 10.0.0 < 10.0.19042.284610.0.19042.2846
microsoftwindows_10_version_21h2>= 10.0.19043.0 < 10.0.19044.284610.0.19044.2846
microsoftwindows_10_version_22h2>= 10.0.19045.0 < 10.0.19045.284610.0.19045.2846
microsoftwindows_11_21h2< 10.0.22000.181710.0.22000.1817
microsoftwindows_11_22h2< 10.0.22621.155510.0.22621.1555
microsoftwindows_11_version_21h2>= 10.0.0 < 10.0.22000.181710.0.22000.1817
microsoftwindows_11_version_22h2>= 10.0.22621.0 < 10.0.22621.155510.0.22621.1555
microsoftwindows_server_2008
microsoftwindows_server_2008_r2_service_pack_1>= 6.1.7601.0 < 6.1.7601.264666.1.7601.26466
microsoftwindows_server_2008_service_pack_2>= 6.0.6003.0 < 6.0.6003.220156.0.6003.22015
microsoftwindows_server_2012
microsoftwindows_server_2012>= 6.2.9200.0 < 6.2.9200.242166.2.9200.24216
microsoftwindows_server_2012_r2>= 6.3.9600.0 < 6.3.9600.209196.3.9600.20919
microsoftwindows_server_2016>= 10.0.14393.0 < 10.0.14393.585010.0.14393.5850
microsoftwindows_server_2019>= 10.0.17763.0 < 10.0.17763.425210.0.17763.4252

Detection & IOCsextracted from sources · hover to see the quote

pathC:\Users\Public.container
pathC:\Users\Public\MyLog_.blf
pathC:\Users\Public\p_*
hash46168ed7dbe33ffc4179974f8bf401aa
registryHKEY_LOCAL_MACHINE\SAM
filenameclfs.sys
  • Exploit artifact files dropped under C:\Users\Public\ — monitor for creation of .blf files and files matching p_* pattern in that directory
  • The exploit triggers vulnerability via the AddLogContainer API call leading to CClfsBaseFilePersisted::ExtendMetadataBlock; monitor for unusual .blf file creation followed by AddLogContainer calls from non-system processes
  • Exploit uses NtQuerySystemInformation with SystemExtendedHandleInformation (class 0x40) to leak kernel addresses; monitor for Medium IL processes calling NtQuerySystemInformation with class 0x40
  • CVE-2023-28252 exploit modifies LogBlockHeader->ValidSectorCount and fields in LogBlockHeader->Record[0] for both CONTROL and CONTROL_SHADOW metadata blocks in a .blf file; forensic analysis of .blf files for these field modifications can identify exploitation attempts
  • ·Microsoft does not document the .blf (base log file) format; the exploit manipulates undocumented kernel structures within .blf files. Exact field names and values that trigger CVE-2023-28252 were intentionally withheld by Kaspersky to allow patching time.
  • ·The vulnerability may be silently masked by exception handlers in clfs.sys, meaning crash-based fuzzing may not detect exploitation attempts — behavioral monitoring is required
  • ·The NtQuerySystemInformation kernel address leak technique used by the exploit requires Medium Integrity Level (Medium IL); it does not work from Low IL processes, limiting exploitation to already-elevated (at least medium IL) user contexts

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
vulncheck7.8HIGH
cisa7.8HIGH
vendor_msrc7.8HIGH
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