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

Static analysis result for SHA-256 9ae676416a3c62a2…

MALICIOUS

Office (OOXML) / .XLSX

45.3 KB Created: 2020-02-01 18:28:07 UTC Authoring application: Microsoft Excel 12.0000
MD5: d78f53cc96deb99233d0020184c39adc SHA-1: 67246b87ed8f6ecce40533a3ce39a2c7e5860977 SHA-256: 9ae676416a3c62a27275c2c6f7a8cf5479b5820e01d9df682e77e4843a2c9fe6
500 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.003 Windows Command Shell T1204.002 Malicious File

The OOXML file contains VBA macros, including an Auto_Open macro, which is a common technique for initial execution. The script utilizes WScript.Shell and Shell() to execute a Base64-decoded command that downloads a second-stage executable from the URL http://198.12.66.107/sNyYAvU.exe. This indicates a dropper functionality designed to fetch and run further malicious content.

Heuristics 11

  • 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.
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
  • VBA Base64-decoded Shell command stager critical OLE_VBA_BASE64_SHELL_COMMAND_STAGER
    VBA auto-exec macro decodes Base64 string literals into command or script-launch text and executes the result with Shell. This catches cmd/cscript/PowerShell/VBS launchers hidden from plain keyword matching.
    URL http://198.12.66.107/sNyYAvU.exe
  • ClamAV: Xls.Dropper.Agent-7669791-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-7669791-0
  • 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
35a90118d311920df516bdddc1004e28cffc8bad247cac92578185c9663deb78		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 38961 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 shell/COM execution token(s). 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
49f668e4d7ce440cbbe3b646a9458678b74aa114cc0ea55bcf3bb2d16a06f9d5		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 3584 bytes
ooxml_oleobject_00_ole10native_00.bin
0ee490e623853b59cac34be1ac1fe82a1ec74de7ac324520fa11864ae314e909		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: Ole10Native 982 bytes
ooxml_oleobject_01.bin
ca62fa9ff0d251ea52367194b508fb5029d2834a4d48e760feaae762e752d014		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject3.bin 5936 bytes
ooxml_oleobject_02.bin
38652f283d3e68f223f3a78df95a9d30988990c1c9863b99b9e408ebe91c3292		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject2.bin 9216 bytes
ooxml_oleobject_02_ole10native_00.bin
f589916a14fdcaed75d1014843d442e381c62fa74df079c84ae99432552aa265		 ole-package OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native 6385 bytes
ooxml_oleobject_03.bin
dffa255438a6eb76613e12d7e6ac397bedca32afa7bae26386aeeb4471c0b905		 ooxml-ole-object OOXML embedded OLE part: xl/vbaProject.bin 64000 bytes
Detection
ClamAV: Xls.Dropper.Agent-7669791-0
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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