Office (OOXML) / .XLSX malware analysis — malicious · 502fed78c758e254

MALICIOUS

Office (OOXML) / .XLSX

152.4 KB Created: 2020-03-25 22:58:42 UTC Authoring application: Microsoft Excel 15.0300

MD5: 872db1a9d981babeb58d831ee441cb87 SHA-1: 4e9eb56f441675dea75e9f5b6da78e80709f8a80 SHA-256: 502fed78c758e254768aebf135fa07ffa92f3ab1343b06ddc902b42c98dfd81b

340 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.003 Windows Command Shell

The file is an Excel spreadsheet containing a Workbook_Open macro, which is a common technique for auto-execution. The macro utilizes character-shifting functions (Asc, Chr, Mid) to decode and execute a command via Shell(). This indicates a downloader or dropper functionality, likely fetching and running a secondary payload. ClamAV detection further supports its malicious nature.

Heuristics 7

Shell() call in VBA critical OLE_VBA_SHELL

Shell() call in VBA
VBA character-shift decoded Shell command critical OLE_VBA_ASC_CHR_SHIFT_SHELL

VBA auto-exec macro stores an encoded command string, decodes it with a Mid/Asc/Chr character-shift loop, and passes the recovered text to Shell. This is a high-confidence command stager.
ClamAV: Xls.Dropper.Agent-7640732-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Dropper.Agent-7640732-0
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
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

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `b805b01d6c3ae63709bf18b4308e0ce54fdf05d9ca7638ff6ac273444210e493`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	2537 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` `0ae08a62f5bdff7daf968fda59f1ac7d25500a5e97880e49e9ed5d942c419b2e`	vba-project	OOXML VBA project: xl/vbaProject.bin	14848 bytes
Detection ClamAV: Xls.Dropper.Agent-7640732-0 Obfuscation or payload: likely Carved macro source contains an auto-exec entry point and execution/download terms.

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