Xls.Downloader.94c25b356b5a6cac-9978798-0 — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 ca2d9eced06bad4e…

MALICIOUS

Office (OLE) / .XLS

2.00 MB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel First seen: 2023-06-19
MD5: 7f0038353ad5e4e4c82fc3ed30769de7 SHA-1: a842e93df3b9aa9d823274ecb0abb31d8bcaffa0 SHA-256: ca2d9eced06bad4e3de7e6a49a603a0dbc8d6eb7ee2af9ccc68222db8aacfc94
292 Risk Score

Malware Insights

Xls.Downloader.94c25b356b5a6cac-9978798-0 · confidence 95%

MITRE ATT&CK
T1204.002 Malicious File T1566.001 Spearphishing Attachment

The file is an Excel spreadsheet containing an embedded Equation Editor object that exploits CVE-2017-11882. This object is designed to drop and execute a secondary PDF payload. The ClamAV detection indicates this is a known downloader variant.

Heuristics 8

  • Equation Editor Ole10Native payload — CVE-2017-11882 critical CVE likely CVE_2017_11882_EQUATION_OLE10NATIVE
    An embedded Microsoft Equation 3.0 object (CLSID 0002CE02-0000-0000-C000-000000000046) carries an Ole10Native packager stream instead of the normal Equation Native/MTEF data. This is the weaponized Equation Editor RCE delivery shape used by CVE-2017-11882 / CVE-2018-0802 maldocs. The payload (font-record overflow + shellcode) is frequently encrypted and the stream name case-scrambled to evade scanners, but an Equation object holding an Ole10Native stream has no benign use.
  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Contains Equation Editor object — related to CVE-2017-11882 / CVE-2018-0802 exploitation, but CLSID presence alone is not the malformed MTEF exploit primitive.
  • Secondary embedded PDF body has suspicious static findings critical POLYGLOT_CHILD_PDF_STATIC_TRIAGE
    A valid PDF body was found at a nonzero offset inside another container and its carved contents matched PDF exploit or lure heuristics. This catches polyglots where the top-level magic routes to ZIP/OLE while a PDF reader or downstream parser opens the hidden PDF payload.
  • ClamAV: Xls.Downloader.94c25b356b5a6cac-9978798-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.94c25b356b5a6cac-9978798-0
  • 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.
  • VBA project contains no executable statements low OLE_VBA_MACROS
    Document contains a VBA project, but extracted modules only contain attributes/options/comments and no executable statements.
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/pdf/1.3/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/iX/1.0/
    • http://www.iec.ch

Extracted artifacts 7

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
7f506327609c082af1cd37dde23bc2c71a000f7d1ef530b6abb66775040a7673		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 1206 bytes
ole10native_00.bin
586b791548031226702675663cbac0a2bd5f1c2a5f8670f11e44fd8acd2ba3b8		 ole-package OLE Ole10Native stream: MBD00054786/ole10natiVE 1728 bytes
stream_005_off00021c15.bin
687dc13e09bd40942bfe2843bb5e4d3d7207221c46649b167abab388296f27c6		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x21C15 39292 bytes
icc_00_off00013f99.icc
2b3aa1645779a9e634744faf9b01e9102b0c9b88fd6deced7934df86b949af7e		 pdf-icc-profile PDF ICC profile at offset 0x13F99 3144 bytes
polyglot_child_pdf_off00008400.pdf
2b60ed9cefd98f1ddaf7b7cacc4d168fe5abf3dfe064bd0c4cac3ca9c4cc89b7		 polyglot-child-pdf Secondary PDF body inside ole container at offset 0x8400 2064896 bytes
Detection
ClamAV: Xls.Downloader.94c25b356b5a6cac-9978798-0
Obfuscation or payload: unlikely
polyglot_child_pdf_off0001dc00.pdf
f577701427a9426daefef79760c6c381938304e9fe3909724a9203cea84f5722		 polyglot-child-pdf Secondary PDF body inside ole container at offset 0x1DC00 1976832 bytes
Detection
ClamAV: Xls.Downloader.94c25b356b5a6cac-9978798-0
Obfuscation or payload: unlikely
polyglot_child_pdf_off00099600.pdf
985ea7d2c0a69dc5540e111fb243af7bab0a2d245bd9480d079f1ded973da7af		 polyglot-child-pdf Secondary PDF body inside ole container at offset 0x99600 1470464 bytes
Detection
ClamAV: Xls.Downloader.94c25b356b5a6cac-9978798-0
Obfuscation or payload: unlikely

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