Malicious PDF — malware analysis report

Static analysis result for SHA-256 633c85d6178047a8…

MALICIOUS

PDF

77.6 KB Created: 2021-03-31 22:00:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-13
MD5: e8024ed81a5320b7ff5171825f610fb0 SHA-1: 5f49c3fdff356c54adb72ccc30c999d84950c633 SHA-256: 633c85d6178047a8edb1888158c1c204333a8288d1808ed692329a2dd473850e
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains numerous external links, with a significant portion pointing to disposable hosting, indicating a link farm or SEO manipulation tactic. The primary URL, 'https://zajinet.ru/wix?keyword=what+are+the+six+types+of+context+clues', suggests a lure to a content-related page. The ML classifier strongly flagged this PDF as malicious, supporting the assessment of a malicious intent behind the link farm.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • 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://zajinet.ru/wix?keyword=what+are+the+six+types+of+context+clues PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4485322/normal_5fe904807fadb.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4479921/normal_5ff1088201c95.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4385197/normal_601d832c87f19.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://6f2fb29c-15f2-4b08-b525-3eb91a7f0a41.filesusr.com/ugd/c3548c_ebf707cf48434e768cedfcb4a4dfb3e1.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/3bfc5654-6b9a-403c-ba53-e1f7e96aa172/dewalt_compressor_d55146_not_building_pressure.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/07b25532-32de-43d5-a7d1-0e599b70adce/how_to_tell_if_im_an_infj.pdfIn PDF document text
    • https://s3.amazonaws.com/wazagidonux/vegitatipo.pdfIn PDF document text
    • https://s3.amazonaws.com/pisedij/silicon_power_formatter.pdfIn PDF document text
    • https://f55c6975-0091-4942-a106-dc80285e5f9d.filesusr.com/ugd/8a4248_9163a69c19f346e88866d023bedd766b.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/7f504920-1426-4fe5-91d9-afea405a5b39/xapofiwuru.pdfIn PDF document text
    • https://8a5a474a-a671-4857-921d-d1df0ee72544.filesusr.com/ugd/523716_436c36ea418b4383a41215fdb2426f51.pdf?index=trueIn PDF document text
    • https://cdfb6f36-dde2-4af5-b3b7-55ff39976061.filesusr.com/ugd/c6ac46_5ca67238fd3b4d38b8ea7e618d2ca286.pdf?index=trueIn PDF document text
    • https://2386e270-bd20-42c1-b3e5-1ba7eaa1d68d.filesusr.com/ugd/b4f0c6_0d7e0c4988ec4e4fb4048b9779c622cb.pdf?index=trueIn PDF document text
    • https://f64a1a0a-debf-4843-a838-a34c0cae0f4a.filesusr.com/ugd/89602e_d4c496b3e13b476da345fdeb683f6652.pdf?index=trueIn PDF document text
    • https://f3dbd103-cf2f-44fc-b0ad-c9004dc38af2.filesusr.com/ugd/1f2646_6313f85940e84811991344235a7f315b.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/dutimajizowa/common_purslane_nutritional_information.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/85d22884-d290-4888-9d0f-529971717caa/why_90_days_sober.pdfIn PDF document text
    • https://cf075d60-af7c-4c71-a16c-5c8c125a9bb7.filesusr.com/ugd/cc03df_55e67ba1349b4e29906d575ea7fbd9b0.pdf?index=trueIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f06b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF06B 5288 bytes
SHA-256: 16971b3130f8ddc9850c39582286e0b0d80976dfbec03bec963f772f4c660964
font_01_sfnt_off0001027d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1027D 10756 bytes
SHA-256: 70385685ae99505a9f4772d9e44d9768c32334e9b752dc01d751a0f586fc73d5