Office (OOXML) / .XLSM malware analysis — malicious · c2672e6fd55b1291

MALICIOUS

Office (OOXML) / .XLSM

102.2 KB Created: 2021-08-19 14:03:52 UTC Authoring application: Microsoft Excel 15.0300

MD5: 6903940ad6060424129a81364b2e2e97 SHA-1: d39323be0e24ee5b72b798e77913509321dcd805 SHA-256: c2672e6fd55b129125a19c7837943c0844c03ec02dcf165af183f9e4df4dccbc

382 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File T1059.003 Windows Command Shell

The Workbook_Open macro executes a command using cmd.exe to download a batch file from 'http://3.112.243.28/net/Ugrfa.bat' using certutil.exe, and then executes the downloaded file named 'Opcbuyjhg.exe.exe'. This indicates the macro's purpose is to download and execute a second-stage payload. The ClamAV detection 'Xls.Dropper.EPPlus-9802867-2' further supports its classification as a dropper.

Heuristics 9

Shell() call in VBA critical OLE_VBA_SHELL

Shell() call in VBA
LOLBin reference in VBA critical OLE_VBA_LOLBIN

LOLBin reference in VBA
ClamAV: Xls.Dropper.EPPlus-9802867-2 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Dropper.EPPlus-9802867-2
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
cmd.exe reference in VBA high OLE_VBA_CMD

cmd.exe reference in VBA
Suspicious extracted artifact high 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.
VBA project inside OOXML medium OOXML_VBA

Document contains vbaProject.bin — VBA macros present
Embedded URL info EMBEDDED_URL

One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.

URL http://3.112.243.28/net/Ugrfa.bat

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `24cb546dc595fd2335678717e88a169676df5932882d8cbe7d604ce7d2dcbb1d`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	1086 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved macro source contains an auto-exec entry point and execution/download terms.
`vbaProject_00.bin` `e0e7c73b8f4f8a45c5e6f2f611806e8589306209d53b6a667d89a1954757f93d`	vba-project	OOXML VBA project: xl/vbaProject.bin	5632 bytes
Detection ClamAV: Xls.Dropper.EPPlus-9802867-2 Obfuscation or payload: unlikely

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