Office (OOXML) / .XLSX malware analysis — malicious · 940f8a9595a2e389

MALICIOUS

Office (OOXML) / .XLSX

145.2 KB Created: 2020-04-15 20:51:40 UTC Authoring application: Microsoft Excel 15.0300

MD5: 94ec6732aef11f4dad2832672b0ad91d SHA-1: c5e2689f84cfe6d5d55ea6226afebad06a31ac39 SHA-256: 940f8a9595a2e38936f5c31e19c4569ac1b10f15d08c30b1a987087857b8d03a

320 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.003 Windows Command Shell T1204.002 Malicious File

The XLSX file contains a Workbook_Open macro that utilizes WScript.Shell and CreateObject to execute a command. This command is obfuscated using character shifting (Asc/Chr/Mid) but ultimately calls Shell() to download and execute a second-stage payload. The presence of these critical heuristics strongly indicates a macro-based downloader.

Heuristics 7

Shell() call in VBA critical OLE_VBA_SHELL

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

WScript.Shell usage
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.
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` `767f82c0adb6ae500bda3e43941a348c67e9f9d8b2a7b3663131fb9016cb030b`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	2163 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` `2baf9d7b51b06e11492b67720713487c4c022c46f4e0f40b1e3eb8d2c61e36a3`	vba-project	OOXML VBA project: xl/vbaProject.bin	14848 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.

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