[BreachExchange] Winnti Hacker Group Uses New Malware to Hack Microsoft SQL Servers

[Destry Winant]

https://gbhackers.com/microsoft-sql-servers/

Winnti hacker group uses a new malware dubbed skip-2.0 to attack
Microsoft SQL Servers and to gain persistence access. Winnti group
believed to be operating from China and the group active at least from
2012 and responsible for high-profile supply-chain against Gaming
studios and Software companies.

ESET Security researchers discovered a new malware strain skip.2-0
along with Winnti Group’s known arsenal. The backdoor found to be
targeting MSSQL Server 11 and 12.

Microsoft SQL Servers Under Attack

The backdoor let attackers connect with MSSQL servers through magic
passwords and automatically hides them from the log. This allows
attackers to perform any action on the database content such as
stealthily copy, modify or delete database content.

Researchers found similarities between skip.2-0 along with the
PortReuse backdoor and ShadowPad versions. As like PortReuse backdoor
skip.2-0 also launched through VMProtected launcher that drops the
backdoor.

The Winnti Group’s payload is RC5-encrypted and embedded with
VMProtected launcher’s overlay, the packer contains Inner-Loader.dll
which is used by Winnti Group to inject the backdoor.

The Inner-Loader looks for a process called sqlserv.exe and injects
the payload to the process, “after having been injected and launched
by Inner-Loader, skip-2.0 first checks whether it is executing within
a sqlserv.exe process, then proceeds to find and hook multiple
functions from that DLL.”

The malware hooks the sqllang.dll file and alters multiple functions,
skip-2.0 primarily targets functions related to authentication and
event logging.

“We observed multiple similarities between skip-2.0 and other tools
from the Winnti Group’s arsenal. Its VMProtected launcher, custom
packer, Inner-Loader injector, and hooking framework are part of the
already known toolset of the Winnti Group,” said ESET.

Indicators of Compromise (IoCs)

VMP Loader
18E4FEB988CB95D71D81E1964AA6280E22361B9F
4AF89296A15C1EA9068A279E05CC4A41B967C956
Inner-Loader injector
A2571946AB181657EB825CDE07188E8BCD689575
skip-2.0
60B9428D00BE5CE562FF3D888441220290A6DAC7
sqllang.dll files
4396D3C904CD340984D474065959E8DD11915444
BE352631E6A6A9D0B7BBA9B82D910FA5AB40C64E
D4ADBC3F77ADE63B836FC4D9E5915A3479F09BD4
0BBD3321F93F3DCDD2A332D1F0326142B3F4961A
FAE6B48F1D6EDDEC79E62844C444FE3955411EE3
A25B25FFA17E63C6884E28E96B487F58DF4502E7
DE76419331381C390A758E634BF2E165A42D4807
ED08E9B4BA6C4B5A1F26D671AD212AA2FB0874A2
1E1B0D91B37BAEBF77F85D1B7C640B8CC02FE11A
59FB000D36612950FEBC36004F1317F7D000AA0B
661DA36BDD115A1E649F3AAE11AD6F7D6FF2DB63