Analysis by: Ryan Paolo Maglaque
 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Rootkit

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware, Downloaded from the Internet

This Rootkit arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size: 57,040 bytes
File Type: SYS
Memory Resident: Yes
Initial Samples Received Date: 08 Jun 2017
Payload: Others

Arrival Details

This Rootkit arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Other Details

This Rootkit does the following:

  • Adds filter on tcp/ip based networks
  • It uses RtlGetVersion to check os version
  • Hooks the following IRP major functions:
    • IRP_MJ_CREATE
    • IRP_MJ_CLOSE
    • IRP_MJ_READ
    • IRP_MJ_WRITE
    • IRP_MJ_SHUTDOWN
    • IRP_MJ_DEVICE_CONTROL
  • It disables kernel debugger
  • If the system is older than windows Vista, it will hook the following tcpip.sys functions:
    • IpInjectPkt
    • IpAllocBuff
    • IpFreeBuff
  • If the system is windows Vista or greater, it will hook the following ndis.sys and fwpkclnt.sys functions:
    • NdisAllocateMdl
    • NdisAllocateMemoryWithTagPriority
    • NdisFreeMdl
    • NdisRetreatNetBufferDataStart
    • NdisGetDataBuffer
    • NdisFreeNetBufferListPool
    • NdisFreeGenericObject
    • NdisAllocateNetBufferListPool
    • NdisAllocateGenericObject
    • NdisAdvanceNetBufferDataStart
    • FwpsInjectionHandleCreate0
    • FwpsInjectNetworkSendAsync0
    • FwpsInjectNetworkReceiveAsync0
    • FwpsQueryPacketInjectionState0
    • FwpsInjectionHandleDestroy0
    • FwpsCalloutRegister0
    • FwpsCalloutUnregisterByKey0
    • FwpmEngineOpen0
    • FwpmEngineClose0
    • FwpmTransactionBegin0
    • FwpmTransactionAbort0
    • FwpmTransactionCommit0
    • FwpmCalloutAdd0
    • FwpmCalloutDeleteByKey0
    • FwpmFilterAdd0
    • FwpmSubLayerAdd0
    • FwpmFilterDeleteByKey0
    • FwpmSubLayerDeleteByKey0
    • FwpsAllocateNetBufferAndNetBufferList0
    • FwpsFreeNetBufferList0
    • FwpsFreeCloneNetBufferList0
  • It creates the following callout filters:
    • CalloutIn
    • CalloutOut
    • CalloutListen
    • CalloutAccept
    • CalloutResource

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.570.04
FIRST VSAPI PATTERN DATE: 02 Aug 2017
VSAPI OPR PATTERN File: 13.571.00
VSAPI OPR PATTERN Date: 03 Aug 2017

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Scan your computer with your Trend Micro product to delete files detected as RTKT64_KERLISEN.B. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


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