Office (OLE) / .XLSX malware analysis — malicious · 4d4627a9fb8a3d61

MALICIOUS

Office (OLE) / .XLSX

78.0 KB Created: 2023-01-26 17:22:13 Authoring application: Microsoft Excel First seen: 2023-01-29

MD5: dab54267f0cebb5ddc6bf9e0e5ebbb28 SHA-1: 1ac453b3f6d88285730aa732fd29da08055cea42 SHA-256: 4d4627a9fb8a3d61d13604cb1a2e689ce1c638170868f08d9fbc862ae1dce1f6

328 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1105 Ingress Tool Transfer T1204.002 Malicious File

The file contains VBA macros, specifically a Workbook_Open event, which is designed to execute automatically when the workbook is opened. The macro utilizes ShellExecuteA and URLDownloadToFile APIs, indicating an intent to download and execute a secondary payload from a remote source. The presence of these APIs and the auto-execution trigger strongly suggest a downloader or droppper functionality.

Heuristics 8

Reference to URLDownloadToFile API critical SC_STR_URLDOWNLOAD

Reference to URLDownloadToFile API
URLDownloadToFile in VBA critical OLE_VBA_DOWNLOAD

URLDownloadToFile in VBA
ClamAV: Xls.Malware.Valyria-10033383-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Malware.Valyria-10033383-0
Reference to ShellExecute API high SC_STR_SHELLEXEC

Reference to ShellExecute API
Workbook_Open macro high OLE_VBA_WBOPEN

Workbook_Open macro
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
Environ() call (env variable access) low OLE_VBA_ENVIRON

Environ() call (env variable access)

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `4fe986bc6ddfc81960def343a4031bff9358889f3c02d16d03c9909c7b2a32c8`	vba-macro	oletools.olevba.extract_macros (decoded VBA source)	17981 bytes

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