Office (OLE) / .XLS malware analysis — malicious · 7b465b9a9814c4e5

MALICIOUS

Office (OLE) / .XLS

358.0 KB Created: 2023-01-08 06:28:17 Authoring application: Microsoft Excel First seen: 2023-01-09

MD5: 42106f299d14ba3b614c894c1bf62bae SHA-1: e1852cfc2d22f5da8a5593dcc7d96a290e5c3496 SHA-256: 7b465b9a9814c4e59b6d334e8af6d359c52d3f8dc495db1ce4a03c2e58f18fb6

328 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic for Applications T1105 Ingress Tool Transfer T1059.003 Windows Command Shell

The Workbook_Open macro automatically executes upon opening the spreadsheet. It uses URLDownloadToFileA to download a payload from "http://example.com/payload.exe" to the user's AppData directory as "payload.exe". Subsequently, ShellExecuteA is called to execute the downloaded file, indicating 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-10033796-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Malware.Valyria-10033796-0
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` `10c0dc7717ef3a4f3a2f61c2401b35e1633ce40a93db2e0b8f9ab2f92edcfa71`	vba-macro	oletools.olevba.extract_macros (decoded VBA source)	744576 bytes

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