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Yet another secret of hosts file

February 18, 2021 in Anti-*, Anti-Forensics, Archaeology, Compromise Detection

In my old post I mentioned not a very well known hosts.ics file. Today I cover one more secret that I stumbled upon while digging inside DNS API internals.

Turns out that dnsapi.dll and dnsrslvr.dll use an internal function called Util_IsRunningOnXboxOne to determine if the DLL is loaded on a XBOX system. And if it is, the path to hosts and host.ics files will not be resolved as relative to the path retrieved via GetSystemDirectory API, but by using a hard-coded XBOX path below:

s:\windows\system32

So, in theory, if you patch Util_IsRunningOnXboxOne function to return 1 (XBOX) you should be able to redirect local DNS requests via hosts(.ics) files to the following paths, respectively:

s:\windows\system32\drivers\etc\hosts
s:\windows\system32\drivers\etc\hosts.ics

Last, but not least – in case you don’t know, the hosts files can be saved using UTF-8, Unicode16-LE, and Unicode16-BE encoding (BOM is being checked).

A few more anti-sandbox tricks…

May 31, 2020 in Anti-*, Sandboxing

Update 2021-01-02

Added VirusTotal Sysmon, C2AE, Sangfor ZSand

Update 2020-06-03

Added more details on MOVES, HABO and Jujubox

Old Post

Today I spotted an article comparing various sandboxes being posted on Twitter. I noticed many of sandboxes present on VirusTotal were not covered in that article so I reviewed a couple of reports and added these sandboxes to the list. While doing so, I picked up a few sandbox characteristics that seem to be fixed, and as such, can lead to programmatic identification of these solutions. In my opinion, sandboxes that don’t provide a randomized environment (different user, different system profile) are relatively easy to detect and sandbox creators need to take this into account to ensure their products remain stealthy. Also, providing screenshots is one of the easiest way to make profile available to attackers. I wonder if creating a fake desktop image could help here (window sized to the screen/workarea resolution and presenting a picture of a fake desktop)

Below are notes I took:

JujuBox

  • User: masked in reports as <USER>, but SID is not
  • SID: S-1-5-21-364843204-231886559-199882026-1001
  • OS version: not licensed and detectable via a trick I described a few days ago
  • Desktop includes Acrobat Reader, Firefox, Google Chrome, Open Office 4.1.6, Steam, accounting, eula, mydoc, mypresentation, OpenOffice, party, and stats — file extensions are not shown, but easy to guess
  • filename is a <SHA256 hash>.exe
  • Screen resolution seems to be low – 800x 600?
  • Only 4 icons on the taskbar


VenusEye

  • User: debug4fun

Yomi Hunter

  • User: j.yoroi

NSFOCUS POMA

  • OS: XP
  • User: sys
  • File: C:\Windows\Temp\sample\<md5>_<sha256>.exe

BitDam ATP

  • User: trans_iso_0

QiAnXin RedDrip

  • User: Administrator
  • System language: zh-CN

Tencent Habo

  • User: Administrator
  • SID: S-1-5-21-1482476501-1645522239-1417001333-500
  • File: sample.doc
  • Hostname: ANALYST<DIGIT>-<HEX>
  • OS: XP (refers to C:\Documents and Settings\Administrator)
  • System language: zh-CN
  • Directory present:
    • C:\DiskD
  • File: 996e.exe (this file name is so prevalent that it even raises questions on Reddit); wild speculation: I wonder if it comes from a Unicode character Ux996E (щео) which means ‘drink’; the reports attempt to remove information about the process name, but do so inefficiently as shown on the below screenshot
  • Other possible fingerprints:
    • OFFICE11 (C:\Program Files\Microsoft Office\OFFICE11\WINWORD.EXE)
    • Python
      • C:\Python\Python27
      • C:\Python\Python36

SecondWrite

  • User: Virtual
  • File: <hash> of the file and starts from %TEMP%\<hash>.exe

Dr.Web vxCube

  • Hides lots of information from the report, these guys know what they are doing (e.g. sample path is listed as <PATH_SAMPLE.EXE>)
  • OS: XP
  • Other possible fingerprints:
    • %CommonProgramFiles(x86)%\microsoft shared\vs7debug\mdm.exe
    • Office14 (%ProgramFiles%\microsoft office\office14)

Rising MOVES

  • User: Administrator
  • System language: zh-CN
  • Service present:
    • badrv
  • Kernel Driver present:
    • rs_badrv
  • Files present:
    • c:\analyse\drop_files.zip
    • c:\analyse\result.zip
    • C:\analyse\log.log
    • C:\analyse\analyzer.exe
    • c:/analyse/gen_report.py
    • C:\Program Files\Qemu-ga\gspawn-win32-helper.exe
  • Mutex:
    • ba_probe_event_memory_mutex

VirusTotal Cuckoofork

  • User: admin
  • Hostname: USER-PC
  • Other possible fingerprints:
    • starts sample from c:\ root directory
    • filename is a SHA256 hash

Lastline

  • User: Johnson, Olivia (randomized)
  • Other possible fingerprints:
    • Office14
      • C:\Program Files (x86)\Microsoft Office\Office14\WINWORD.EXE
    • Office16
      • C:\Program Files\Microsoft Office\Root\Office16\WINWORD.EXE

VMRay

  • User: nice to see proper randomization e.g. ‘aETAdzjz’
  • Other possible fingerprints:
    • Office16
      • C:\Program Files\Microsoft Office\Root\Office16\WINWORD.EXE

VirusTotal Box of Apples

  • User: user1

OS X Sandbox

  • Other possible fingerprints:
    • VMWare path mapped
      • Library/Filesystems/vmhgfs.fs

VirusTotal Androbox

  • n/a

VirusTotal Droidy

  • User: user

VirusTotal C2AE (this is not CAPEv2, thx @doomedraven)

  • Very weak rule: processes present at the time of execution, and soon after terminated:
    • %windir%\System32\svchost.exe -k WerSvcGroup
    • wmiadap.exe /F /T /R
  • “%SAMPLEPATH%” is probably a better option, just need to get lucky to get it resolved using a test sample

VirusTotal Sysmon

  • User: admin
  • Process launched as “C:\Users\admin\Downloads\<MD5>.mlw.exe” OR
  • Process launched as “C:\Users\admin\Downloads\<MD5>.virus.exe”

Sangfor ZSand

  • Process starts from c:\