Office (OLE) / .XLS malware analysis — malicious · 13d9c1e02ffcc1ed

MALICIOUS

Office (OLE) / .XLS

395.5 KB Created: 2023-04-08 16:07:23 Authoring application: Microsoft Excel First seen: 2023-04-09

MD5: a4bd56efab5980c9634bf4c9f8e802b1 SHA-1: d15b4e48fabb1bfb89e3281434bd12090bce534f SHA-256: 13d9c1e02ffcc1ed257d6200fa4e5faa9b32b8e7dca0e356b271b42b54687a46

270 Risk Score

Malware Insights

MITRE ATT&CK

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

The Workbook_Open macro automatically executes upon opening the spreadsheet. It utilizes the URLDownloadToFile API to download a payload from a remote server and ShellExecuteA to execute it. The obfuscated VBA code and the use of these APIs strongly suggest a downloader 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
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)
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 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `f39dbf01d1363a32acf36bdadd6b8afd07d03823086d346838f602a1f952a4bd`	vba-macro	oletools.olevba.extract_macros (decoded VBA source)	32265 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 15 long base64-like blob(s).

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