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

Static analysis result for SHA-256 cd09cf52ccce786a…

MALICIOUS

Office (OOXML) / .XLSX

47.9 KB Created: 2020-02-01 18:28:07 UTC Authoring application: Microsoft Excel 12.0000
MD5: 420398dd4b6b6fe527803c23c646d121 SHA-1: b04611b0342b11292c797e10ff0907b3f2f87866 SHA-256: cd09cf52ccce786a0e1e640abb277b33520f8aa29367b0678fe22d910ea17006
500 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.003 Windows Command Shell T1105 Ingress Tool Transfer

The file contains a VBA macro with an Auto_Open function that utilizes WScript.Shell to execute a Base64-decoded command. This command downloads and executes a PE file from the URL http://88.218.16.37/EocJyfwjX51UduQ.exe, indicating a downloader or dropper functionality. The presence of an Equation Editor OLE object and ClamAV detections further support its malicious nature.

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://88.218.16.37/EocJyfwjX51UduQ.exe
  • ClamAV: Xls.Dropper.Agent-7687967-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-7687967-0
  • 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
0a2eed9256818873203037453f67c863b50357c9155191a098a3412a4a934b1b		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 45425 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
a4f59656683ba59e88c59cd48669fdb10f2ffd049d16777678129a93c52a2cf0		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject3.bin 5936 bytes
ooxml_oleobject_01.bin
b6d535a85bb8796060a880b519d94762157782f3c61342338bdb51f1b305f1b0		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject2.bin 10240 bytes
ooxml_oleobject_01_ole10native_00.bin
51d69c5dce5e3400c08dcec2c55146966592fd3b3b479b724a0f7533ab9341d6		 ole-package OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native 7317 bytes
ooxml_oleobject_02.bin
6e29d7d282332f1f7ae3aaacc6044c018dfbaddc1479da1a785d5141657b1040		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 3584 bytes
ooxml_oleobject_02_ole10native_00.bin
b7d4ecda1a8b2ac7dddb10bfc77eb599ac8b16b7e133ca7aa3523495ccd6a3f4		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: Ole10Native 967 bytes
ooxml_oleobject_03.bin
c3d135c3831cb1092eaf72228225d499d162f41aee2346f5c901ee11456f10df		 ooxml-ole-object OOXML embedded OLE part: xl/vbaProject.bin 73216 bytes
Detection
ClamAV: Xls.Dropper.Agent-7687967-0
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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