Office (OOXML) / .XLSM malware analysis — malicious · 0eebca5c4174eecc

MALICIOUS

Office (OOXML) / .XLSM

72.4 KB Created: 2020-06-29 18:26:33 UTC Authoring application: Microsoft Excel 14.0300

MD5: f41acbed47044b2588718f457ef8bf2b SHA-1: b85e29bed6977c1d689b057d548882e7058f2648 SHA-256: 0eebca5c4174eecc1f3f8066db7dcafaf96d9d89914617cac3c5ba925010abee

282 Risk Score

Malware Insights

MITRE ATT&CK

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

The critical heuristic 'OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER' indicates an obfuscated auto-exec VBA loader. The Workbook_Open macro, identified by the 'OLE_VBA_WBOPEN' heuristic, contains a call to a 'Loader' subroutine. This subroutine uses 'CreateObject' to instantiate a scripting shell and then executes a PowerShell command to download a file from the hardcoded URL 'http://k0pla.com/order587458.exe' into the temporary directory as 'putty.exe' and subsequently executes it. This behavior is consistent with a macro-based dropper.

Heuristics 7

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: Xls.Dropper.Agent-8878355-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Dropper.Agent-8878355-0
ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV

ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
Workbook_Open macro high OLE_VBA_WBOPEN

Workbook_Open macro
CreateObject call high OLE_VBA_CREATEOBJ

CreateObject call
VBA project inside OOXML medium OOXML_VBA

Document contains a VBA project — VBA macros present
Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE

One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `fe317588034fd1f069a561949f1715f856ab04975955a18a57f9e1d30b7a5809`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	3745 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 long base64-like blob(s).
`vbaProject_00.bin` `44a02747f496978743e5333930e75f289f39a1b828ad9b4f52d1868db8a848c9`	vba-project	OOXML VBA project: xl/vbaProject.bin	5632 bytes
Detection ClamAV: Xls.Dropper.Agent-8878355-0 Obfuscation or payload: unlikely

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