Malicious PDF — malware analysis report

Static analysis result for SHA-256 ac5e8e3c857a2f61…

MALICIOUS

PDF

71.1 KB Created: 2021-06-05 22:34:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: 04745916ad3d401e0cd13f6ce7c6edd2 SHA-1: 69b8e5fc1c68397f27ec8aa2060da58ec70c2592 SHA-256: ac5e8e3c857a2f61220c7201baf39505c8a6601eb6417ac37acde1f4caf1c924
96 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs pointing to compromised WordPress sites and disposable domains, indicating a link farm designed to redirect users. The ML classifier strongly flagged this PDF as malicious, and the heuristic firings suggest it's part of a link farm strategy. No scripts were extracted, but the primary attack pattern involves luring users through these links, potentially to a phishing site or to download further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 https://laborke.ru/uplcv?utm_term=simple+piano+pieces+pdf PDF link annotation
    • http://geometrabottero.it/userfiles/files/vavusekedogodode.pdfIn PDF document text
    • https://directprocessors.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cd74b8389d---farorododukaxik.pdfIn PDF document text
    • http://com123.vn/uploads/file/temejakegedawu.pdfIn PDF document text
    • http://nordicaluminium.ru/userfiles/file/17186412907.pdfIn PDF document text
    • https://www.officinadelgustoroma.com/wp-content/plugins/super-forms/uploads/php/files/ac2110e3f632792d6877af2edb2a137a/88673107066.pdfIn PDF document text
    • https://www.landalastadservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/160793b6642f18---perolojiziputumakanivedu.pdfIn PDF document text
    • http://sakirnoopo.ru/wp-content/plugins/super-forms/uploads/php/files/02f958da54da8ed0e725b6fd3a071873/27518384125.pdfIn PDF document text
    • https://earthchartercities.org/wp-content/plugins/formcraft/file-upload/server/content/files/16080cd08d86b5---33771866691.pdfIn PDF document text
    • http://hungthanhauto.com/luutru/files/54152753579.pdfIn PDF document text
    • https://medicinasolidale.org/wp-content/plugins/super-forms/uploads/php/files/ac8ee4376e8af66c7dfc3561672496f3/pidexujenufetigake.pdfIn PDF document text
    • http://www.sempresaude.net/wp-content/plugins/formcraft/file-upload/server/content/files/16088019f1be36---43701838784.pdfIn PDF document text
    • http://eotp.info/sites/default/files/fck/file/tavogunolusipew.pdfIn PDF document text
    • https://xn--80adj7cxa.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/0cdc150f206c3109e7a10d6e5a954fd8/44816514532.pdfIn PDF document text
    • https://angkalaris.com/contents//files/45726383696.pdfIn PDF document text
    • https://www.grecosalesinternational.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609ce1c2715d8---tuwonidawinuw.pdfIn PDF document text
    • https://mudateconmigo.cl/wp-content/plugins/super-forms/uploads/php/files/5c78faab6152973c5ad267b15d31d5d2/sujake.pdfIn PDF document text
    • https://rebel-guitars.com/wp-content/plugins/super-forms/uploads/php/files/a255fbb5f59bf6eaf4e52ce741cabf2c/zipudisefenebow.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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_off0000d9ac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9AC 5308 bytes
SHA-256: 6017a6a06e3b19bd33f47eb7e7d6bd0a50f2bb7bea884a2fa0a3dc57434b5aba
font_01_sfnt_off0000ebaa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEBAA 10512 bytes
SHA-256: 4efad25c6b904bfa582e9681f11567d3766b6d863f5bfd5deed732488eca30da