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

Static analysis result for SHA-256 4a756373b379bbb3…

MALICIOUS

Office (OLE) / .XLSX

1.63 MB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel First seen: 2023-08-25
MD5: 843d1c74272e13b2d539e9e55e311b74 SHA-1: 25cb0dc6dcd6b348cee2bf11b10d8d1347507c7c SHA-256: 4a756373b379bbb33dcf1d48d050ea370440b2390f2bfd4d20ae3e8ab46ca2f2
332 Risk Score

Malware Insights

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

The sample leverages a critical vulnerability in Equation Editor (CVE-2017-11882) to embed a malicious PDF. This PDF contains a direct payload link to 'https://https://www.google.co.in/example.com', indicating a downloader or exploit delivery mechanism. The ClamAV detection 'Xls.Downloader.94c25b356b5a6cac-9978798-0' further supports its role as a downloader.

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://ns.adobe.com/pdf/1.3/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/

Extracted artifacts 6

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
819924ca8bbf1f506c80462d747dd6880a31bb17ab53e0981f9afa2147a3757d		 ole-package OLE Ole10Native stream: MBD0041C475/Ole10NatIvE 1602 bytes
polyglot_child_pdf_off0005c200.pdf
330d535bcba4f623474288848ded9a0412051200a6e8b6cf0ccf6ce3b570bf22		 polyglot-child-pdf Secondary PDF body inside ole container at offset 0x5C200 1327104 bytes
polyglot_child_pdf_off00001200.pdf
b0c1788ef4416d1c09db894920e945b946fe2a431c67e8512036c8d1357fd841		 polyglot-child-pdf Secondary PDF body inside ole container at offset 0x1200 1699840 bytes
polyglot_child_pdf_off00006600.pdf
d466106cb07ad8a9c33b11021a2aa24aab6f403b1f7d0f1f3c579431deb37185		 polyglot-child-pdf Secondary PDF body inside ole container at offset 0x6600 1678336 bytes
polyglot_child_pdf_off00019000.pdf
637a6372bab5d850220b171602f150e2dba7f64d61adb81d8f49b387950b6bfe		 polyglot-child-pdf Secondary PDF body inside ole container at offset 0x19000 1602048 bytes

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