Malicious Office (OOXML) / .XLSM — malware analysis report

Static analysis result for SHA-256 ea0a6f7187a27e0a…

MALICIOUS

Office (OOXML) / .XLSM

50.6 KB Created: 2020-02-01 18:28:07 UTC Authoring application: Microsoft Excel 12.0000
MD5: 6e9d5a8f06f4fc46ee536d6dcd15af3e SHA-1: 0f278a2983d93c1dbbc88b43f6520f789542e1fb SHA-256: ea0a6f7187a27e0a7b61c2263925e116530df8dfcd4f3d1c0a61caf64faa51c6
380 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1059 Command and Scripting Interpreter T1059.003 Command and Scripting Interpreter: Windows Command Shell T1566 Phishing T1566.001 Phishing: Spearphishing Attachment

The sample is an XLSM file containing VBA macros, specifically an Auto_Open macro, which is a common delivery mechanism. It exploits CVE-2017-11882 through an embedded Equation Editor object. This exploit attempts to execute a command-line stager, indicated by the critical heuristic 'CVE_2017_11882_EQUATION_NATIVE_CMD'. The command executed appears to be 'cmd /c REn %tmp%\q v& WsCRIpT %tmp%\v?..wsf ..C...', suggesting it downloads and executes a second-stage payload using scripting. ClamAV detections further confirm its malicious nature as a dropper.

Heuristics 9

  • 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.
  • ClamAV: Doc.Dropper.Detected-9977031-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Detected-9977031-0
  • 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
  • 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
  • Embedded OLE object medium OOXML_OLE_OBJECT
    Document contains an embedded OLE object

Extracted artifacts 9

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
57acd1d271d9e8097df825acaf641b16f3a5ca0a90af2eb33515498655b55af6		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 23791 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s). Carved macro source contains an auto-exec entry point and execution/download terms.
ooxml_oleobject_00.bin
6f358b893b9b19f967aa138c22180048fe725b25d1d0be1e9f4243851efe17d6		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject2.bin 15872 bytes
ooxml_oleobject_00_ole10native_00.bin
63b60e6c3bb068db67fa1ae7c9e07c7eeeefdd1ac51dcfbab69008a496a98c9a		 ole-package OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native 13253 bytes
ooxml_oleobject_01.bin
dea16f07fdbd87b841415195e9278d6d407728b2c40c4b5bf742bbb0750cbde1		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 13312 bytes
ooxml_oleobject_01_ole10native_00.bin
4b47fa8f2a111c278ca209bb39497be7bce99db078a1428681791ca0f07e926a		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: Ole10Native 10290 bytes
ooxml_oleobject_02.bin
f511c7cf1066799b9a091ba24563f15bef83a456d4ba8703f8564b49255e72d7		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject3.bin 5936 bytes
ooxml_oleobject_03.bin
ebc6836ed1d0b145ffd5af079101c94605a86a49efaef5e56576e72673a6996c		 ooxml-ole-object OOXML embedded OLE part: xl/vbaProject.bin 47616 bytes
Detection
ClamAV: Doc.Dropper.Detected-9977031-0
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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