Office (OLE) / .XLS malware analysis — malicious · 06e5df797118033b

MALICIOUS

Office (OLE) / .XLS

105.5 KB Created: 2021-12-29 06:52:36 Authoring application: Microsoft Excel First seen: 2022-03-30

MD5: f38fe660ebaceda4b8541f141b6904e3 SHA-1: 9192f8cf50b35a452454469ae1b14419afd395a0 SHA-256: 06e5df797118033b57357027e9b01fe98fa13f0b0a3e8c85cf6563b76eb9d4f4

320 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1204.002 Malicious File T1140 Deobfuscate/Decode Files or Information

The sample is a macro-enabled Excel file containing obfuscated VBA code that executes upon opening. The Workbook_Open subroutine calls a function that constructs a path to 'putty.exe' and attempts to download it from 'http://192.168.1.100/putty.exe'. The use of CreateObject and Shell() calls indicates an attempt to execute a downloaded payload.

Heuristics 7

Shell() call in VBA critical OLE_VBA_SHELL

Shell() call in VBA
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.
ClamAV: Doc.Downloader.DocuSign04220-9942585-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Doc.Downloader.DocuSign04220-9942585-0
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 macros detected medium OLE_VBA_MACROS

Document contains VBA macro code

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `665f09781fb250e14f44733a22419dd8ce9101e4657189e6d85b9b27b07ab03f`	vba-macro	oletools.olevba.extract_macros (decoded VBA source)	9447 bytes

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