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

Static analysis result for SHA-256 1e0726ca49dea56d…

MALICIOUS

Office (OLE) / .XLS

1.21 MB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel First seen: 2023-10-17
MD5: 8aa133a7c17fdfac47d771974fff146f SHA-1: 6529661288ded9cabc2ff31e2d15909954daaa05 SHA-256: 1e0726ca49dea56d96644ff9aa6dec2cd1492c479cb046590a2e4f64b544d1d2
332 Risk Score

Malware Insights

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

MITRE ATT&CK
T1204.002 Malicious File T1566.001 Spearphishing Attachment T1059.005 Visual Basic

The sample is an Excel file containing an embedded Equation Editor OLE object that exploits CVE-2017-11882. This object contains a secondary PDF payload which, in turn, has a direct link to an executable or archive. The ClamAV detection name 'Xls.Downloader.94c25b356b5a6cac-9978798-0' and the embedded PDF's direct payload link indicate a downloader functionality.

Heuristics 9

  • 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.
  • PDF link points directly to executable/archive payload critical PDF_DIRECT_PAYLOAD_LINK
    PDF contains a clickable HTTP(S) URI whose path ends in an executable, script, shortcut, disk image, or archive extension. Documents can legitimately link to installers, so this is a high-risk delivery indicator rather than a standalone exploit fingerprint.
  • ClamAV: Xls.Downloader.94c25b356b5a6cac-9978798-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.94c25b356b5a6cac-9978798-0
  • Clickable PDF combines external action with parser-evasion structure high PDF_ACTION_PARSER_EVASION
    PDF has an external clickable URI together with object graph or xref structures that make parsers disagree, such as divergent duplicate objects, parser divergence, or xref offset mismatch. That combination is stronger than a plain link: the document is both an outward-action carrier and a parser-confusion/evasion sample.
  • 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 https://https://www.google.co.in/example.com
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/pdf/1.3/

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
3d347f5884acf62dfa578a4b07d8e6afcec43be38f1da065f81aa032b18b510f		 ole-package OLE Ole10Native stream: MBD002131FD/OlE10NaTiVE 1651 bytes
polyglot_child_pdf_off00086e00.pdf
4cbc876a6f34f9dbd39fc95a109044157e838f95e979fadd50a8a574b897707a		 polyglot-child-pdf Secondary PDF body inside ole container at offset 0x86E00 712704 bytes
stream_004_off00005d60.bin
2998a126f4fa11ceb265371a5f7968ec18bc4692a32631a544232dc74040021f		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x5D60 252488 bytes
polyglot_child_pdf_off00001200.pdf
617cdd267476583c9c3f06b16a7064725b5717c3dff9d4d5a7df5aa39783824c		 polyglot-child-pdf Secondary PDF body inside ole container at offset 0x1200 1260544 bytes
polyglot_child_pdf_off00006600.pdf
6fe15290934da9206f4dd9db42d43990cff7fa9ca341280d52a3bcd2875498d4		 polyglot-child-pdf Secondary PDF body inside ole container at offset 0x6600 1239040 bytes
polyglot_child_pdf_off00029600.pdf
bb21ceade3fd2f27bb54445115e5b814360e1796df2e225944a1f1670ce2572c		 polyglot-child-pdf Secondary PDF body inside ole container at offset 0x29600 1095680 bytes

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