From
szz743 user on Microsoft Answers:
"Microsoft Link-Layer Discovery Protocol" binary is located in \Windows\system32\DRIVERS\mslldp.sys
The registry key is here: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MsLldp
During a VSS backup process running as NETWORK_SERVICE, the account calls cryptcatsvc!CSystemWriter::AddLegacyDriverFiles(), which enumerates all the drivers records in Service Control Manager database and tries to open each of them, one at a time. The function fails on MSLLDP record with an
Access is Denied error.
It fails because the MSLLDP driver security permissions don't allow the NETWORK_SERVICE access to the driver record.
The binary security descriptor for the record is located at: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MsLldp\Security
Use SC.EXE and Sysinternals' ACCESSCHK.EXE to fix it:
The original security descriptor looked like this:
>accesschk.exe -c mslldp
mslldp
RW NT AUTHORITY\SYSTEM
RW BUILTIN\Administrators
RW S-1-5-32-549 <- these are server operators
R NT SERVICE\NlaSvc
No service account is allowed to access MSLLDP driver
The security descriptor for the drivers that were processed successfully looked this way:
>accesschk.exe -c mup
mup
RW NT AUTHORITY\SYSTEM
RW BUILTIN\Administrators
R NT AUTHORITY\INTERACTIVE
R NT AUTHORITY\SERVICE <- this gives access to services
How to add access rights for NT AUTHORITY\SERVICE to MSLLDP service:
1. Run: SC sdshow MSLLDP
You'll get something like below (SDDL language is documented on MSDN):
D:(D;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BG)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;SY)(A;;CCDCLCSWRPDTLOCRSDRCWDWO;;;BA)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;SO)(A;;LCRPWP;;;S-1-5-80-3141615172-2057878085-1754447212-2405740020-3916490453)S:(AU;FA;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;WD)
2. Run: SC sdshow MUP
You'll get:
D:(A;;CCLCSWRPWPDTLOCRRC;;;SY)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)(A;;CCLCSWLOCRRC;;;IU)(A;;CCLCSWLOCRRC;;;SU)S:(AU;FA;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;WD)
3. Take NT AUTHORITY\ SERVICE entry, which is (A;;CCLCSWLOCRRC;;;SU) and add it to the original MSLLDP security descriptor properly, right before the last S:(AU... group.
4. Apply the new security descriptor to MSLLDP service :
sc sdset MSLLDP D:(D;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BG)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;SY)(A;;CCDCLCSWRPDTLOCRSDRCWDWO;;;BA)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;SO)(A;;LCRPWP;;;S-1-5-80-3141615172-2057878085-1754447212-2405740020-3916490453)(A;;CCLCSWLOCRRC;;;SU)S:(AU;FA;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;WD)
5. Check the result:
>accesschk.exe -c mslldp
mslldp
RW NT AUTHORITY\SYSTEM
RW BUILTIN\Administrators
RW S-1-5-32-549
R NT SERVICE\NlaSvc
R NT AUTHORITY\SERVICE
