Malicious Office (OOXML) / .XLSM — malware analysis report

Static analysis result for SHA-256 341b44718794505a…

MALICIOUS

Office (OOXML) / .XLSM

443.6 KB Created: 2000-04-13 21:48:14 UTC Authoring application: Microsoft Excel 12.0000
MD5: 9bfe2a9f607d24948d988b07afaec1f0 SHA-1: f5a9c7f5dd987beaeff27534b69c33f167411b2f SHA-256: 341b44718794505a04186aa46c2ed2b5438c17ddbb9b1bbdce5f98737fd389c3
208 Risk Score

Malware Insights

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

The sample is an XLSM file containing a Workbook_Open macro that is heavily obfuscated. The macro uses `CreateObject` to execute a command that appears to download and run a script file named 'getManual5502.sct' from the user's public documents directory using `mshta`. This indicates an attempt to download and execute a second-stage payload.

Heuristics 6

  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • 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.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
a5e2485d13ea048b49682d05344b65d915e5a45bac965c9913f57d60caa25cd7		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1147 bytes
vbaProject_00.bin
0a2f559e6f909d68f303cb3ab5a7022f3d1fbe7167c7805467cdbb5c2b7571ce		 vba-project OOXML VBA project: xl/vbaProject.bin 9216 bytes

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