Office (OOXML) / .XLSX malware analysis — malicious · b416b3cd07533aa1

MALICIOUS

Office (OOXML) / .XLSX

438.7 KB Created: 2021-08-19 14:03:52 UTC Authoring application: Microsoft Excel 16.0300

MD5: 9bf51f7bdf35911324a4fbb9235090f7 SHA-1: d1abcb2b543a4c0f308dade69d1be6a96f356a3b SHA-256: b416b3cd07533aa1e3f322bbf904be65df03dcf08507ef9a683271a3c4848025

440 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.003 Windows Command Shell T1204.002 Malicious File T1105 Ingress Tool Transfer

The file is an Excel spreadsheet containing a Workbook_Open macro. This macro utilizes WScript.Shell and CreateObject to execute obfuscated VBA code. The obfuscated code is designed to download and execute a second-stage payload from a URL, as indicated by the OLE_VBA_OBFUSCATED_SHELL_URL heuristic. ClamAV also identifies the file as Doc.Dropper.Agent-6412232-1.

Heuristics 9

Shell() call in VBA critical OLE_VBA_SHELL

Shell() call in VBA
WScript.Shell usage critical OLE_VBA_WSCRIPT

WScript.Shell usage
Obfuscated VBA Shell command with URL critical OLE_VBA_OBFUSCATED_SHELL_URL

VBA macro invokes Shell with command text assembled through decoder or string-manipulation functions and includes a URL. This is a high-confidence downloader/dropper pattern, stronger than Shell or URL evidence on their own.
ClamAV: Doc.Dropper.Agent-6412232-1 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Doc.Dropper.Agent-6412232-1
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
CreateObject call high OLE_VBA_CREATEOBJ

CreateObject call
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` `3be71b0d18722d5a4f9a7222074f492c59d1f62f11646043db163e8306f24495`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	1280 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 shell/COM execution token(s). Carved macro source contains an auto-exec entry point and execution/download terms.
`vbaProject_00.bin` `35e9fe54d350b9c1a5a58d6f08e96704e0065665622f350ae7fc56a0d2311c94`	vba-project	OOXML VBA project: xl/vbaProject.bin	15872 bytes
Detection ClamAV: Doc.Dropper.Agent-6412232-1 Obfuscation or payload: likely Carved artifact contains 1 shell/COM execution token(s). 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.