Malicious PDF — malware analysis report

Static analysis result for SHA-256 be2536d9192d11ab…

MALICIOUS

PDF

74.6 KB Created: 2021-09-01 23:31:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: cf6a45742801c2a5a06659d472c8b6c3 SHA-1: 20235cad82f64cd520b68d343e870a91b84b3b48 SHA-256: be2536d9192d11ab647b53102e3bdc88203ac6f4a695803af31e194194eea550
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded URLs, many of which point to compromised WordPress sites and disposable domains, indicating a link farm or SEO spamming campaign. The ML classifier strongly flagged this PDF as malicious, and the heuristic firings confirm the presence of external URI links and a link farm structure. No scripts were extracted from this sample, limiting the ability to determine a specific payload or execution method beyond the potential for users to click these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

Heuristics 5

  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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 http://karthikeyanjayaram.com/userfiles/file/dagasajiwipaxawovel.pdf In PDF document text
    • http://www.holderit.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aa85eab8e2b---sijowigamirerebup.pdfIn PDF document text
    • https://www.areatransfers.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b7d435ef8cb---pajopatanijunonovudep.pdfIn PDF document text
    • https://narimasu-chintai.net/jcfiles/file/94627073602.pdfIn PDF document text
    • https://www.blackandwhite-salon.com/wp-content/plugins/super-forms/uploads/php/files/a0fd0fc6777596ecc6b33432ad4a7968/94851747678.pdfIn PDF document text
    • https://www.mercedesbenzofaustinservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c39aa8c96f9---miwubi.pdfIn PDF document text
    • http://familiehollander.nl/images/uploadedimages/file/doxivenuforobimegujon.pdfIn PDF document text
    • https://centar-znr-zop.hr/wp-content/plugins/formcraft/file-upload/server/content/files/1607c9315bd477---rudelebulef.pdfIn PDF document text
    • https://shrmivirtual.org/wp-content/plugins/super-forms/uploads/php/files/ea07fc076645dc87736ab8172dfb2188/5713884405.pdfIn PDF document text
    • http://www.k-24.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c4a7aaa3f99---71158007655.pdfIn PDF document text
    • https://linhquan-group.com/upload/ck/files/72995741623.pdfIn PDF document text
    • http://daglichtfilters.nl/ckfinder/userfiles/files/tekupewonu.pdfIn PDF document text
    • https://alice-immo.com/userfiles/file/50023032337.pdfIn PDF document text
    • http://streathamtaxi.com/survey/userfiles/files/31639923341.pdfIn PDF document text
    • https://hram-uspeniya.ru/ckfinder/userfiles/files/52169528126.pdfIn PDF document text
    • https://momsgardenfoods.com/ckfinder/userfiles/files/72233466411.pdfIn PDF document text
    • http://acupunctuuryao.nl/ckfinder/userfiles/files/27615740721.pdfIn PDF document text
    • http://restorationteleconference.com/clients/73716/File/gimozedesap.pdfIn PDF document text
    • http://stelmart.ru/userfiles/file/23131739588.pdfIn PDF document text
    • http://wohntraumgmbh.at/29750626314.pdfIn PDF document text
    • http://inhome360.ru/admin/ckfinder/userfiles/files/12812665268.pdfIn PDF document text
    • http://kerama.altrodesign.eu/ckfinder/userfiles/files/51671455540.pdfIn PDF document text
    • https://www.frontierexim.com/wp-content/plugins/super-forms/uploads/php/files/4s2unoaeisn6lfa12iku7bmqlb/xunekufejazet.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/cv9VXjIrmdE/uplcv?utm_term=maslow%27s+physiological+needs+may+be+satisfied+byPDF link annotation
    • 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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c2fd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC2FD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000db14.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB14 11336 bytes
SHA-256: b2f76d8e23da8acf2294ce989f943d6823a8d0c912376bee98fa81263a0aa625
font_02_sfnt_off0000f548.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF548 15384 bytes
SHA-256: 2f7e0c8fa2146c983242e18c94acde1909b913d332ef1e8e9b6c5086a29a7287