Office (OOXML) / .XLSM malware analysis — malicious · 68f934543b161bf9

MALICIOUS

Office (OOXML) / .XLSM

47.0 KB Created: 2020-02-01 18:28:07 UTC Authoring application: Microsoft Excel 12.0000

MD5: dea2e31b624dab47fc1e4f7449e2939f SHA-1: fbf43d114ef942e492c7eda4e43e4c261d85a9bc SHA-256: 68f934543b161bf9bfb26cc82e07da65b53dbf7b6cd5bf2921afe1ef113751f5

442 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1059.005 Visual Basic

The sample is an XLSM file containing VBA macros, specifically an Auto_Open macro that utilizes CreateObject. Critical heuristics indicate exploitation of CVE-2017-11882 via the Equation Editor OLE object, which attempts to execute a command. The extracted command, 'cmd /c ren %tmp%\mm v&cSCRIpT %tmp%\v..wsf ..C', suggests the creation and execution of a script file, likely to download and execute a further stage. The VBA code is heavily truncated, preventing a full analysis of its actions, but the primary intent appears to be command execution via the Equation Editor vulnerability.

Heuristics 11

CVE-2017-11882 — Equation Editor command stager critical CVE likely CVE_2017_11882_EQUATION_NATIVE_CMD

Embedded Equation Editor OLE data contains an invalid Equation Native/MTEF stream with an embedded command stager. This is likely CVE-2017-11882 exploitation because the vulnerable Equation Editor component is reached and the malformed native stream directly carries process-launch bytes.
Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/oleObject3.bin contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
Embedded Office object carries macros critical OFFICE_EMBEDDED_MACRO_OBJECT

This document embeds a second Office file that itself contains a VBA macro project or an Excel 4.0 (XLM) macro sheet. Hiding a macro-bearing workbook or document inside another document — frequently under an obfuscated, non-standard part name — is a macro-smuggling technique that defeats scanners which only inspect the outer document's macro storage. No benign authoring workflow stages a hidden macro project this way.
ClamAV: Xls.Malware.Generic-8176608-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Malware.Generic-8176608-0
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.
Auto_Open macro high OLE_VBA_AUTO

Auto_Open macro
CreateObject call high OLE_VBA_CREATEOBJ

CreateObject call
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 project inside OOXML medium OOXML_VBA

Document contains a VBA project — VBA macros present
Embedded OLE object medium OOXML_OLE_OBJECT

Document contains an embedded OLE object
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 9

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `9959372a2f7653aede736b118b4050a982b9bf91d5c15a05e935fed2d195a62b`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	25028 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
`ooxml_oleobject_00.bin` `464959801baf4a495a984dfab3d2962d78f7134048272e31cd1697e25d88b8b7`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject3.bin	5936 bytes
`ooxml_oleobject_01.bin` `aa7d5320383731b056c17aa344da4afaffb0d16dddc7496ef9550677e07c9b7d`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject1.bin	3584 bytes
`ooxml_oleobject_01_ole10native_00.bin` `6530464814e5b1dce7c9fbfa3ac504ae72e8b8751b72a64be45fe1a5bd78ed57`	ole-package	OOXML xl/embeddings/oleObject1.bin Ole10Native stream: Ole10Native	1240 bytes
`ooxml_oleobject_02.bin` `469aa68097b12e7d443ece1c8b958fc4ea4633840e1b57fc10d8c334c09b498b`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject2.bin	12800 bytes
`ooxml_oleobject_02_ole10native_00.bin` `2249813feb73a89e4900431974819553fa626605c1c8e86f539a0fe1020b8880`	ole-package	OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native	9790 bytes
`ooxml_oleobject_03.bin` `fad8d8a989a40f086c6787280a27f0cd1e2ca3e6d20f1a23d637b68252286ee5`	ooxml-ole-object	OOXML embedded OLE part: xl/vbaProject.bin	44032 bytes
Detection ClamAV: Xls.Malware.Generic-8176608-0 Obfuscation or payload: unlikely
`emf_00.emf` `979dde2aed02f077c16ae53546c6df9eed40e8386d6db6fc36aee9f966d2cb82`	ooxml-emf	OOXML EMF part: xl/media/image1.emf	4968 bytes
`emf_01.emf` `4d4d1e7b04c99dcb8e885915068ad6f74cc2333e91580cdae5ccaa00c427247f`	ooxml-emf	OOXML EMF part: xl/media/image2.emf	1536 bytes

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