Malicious PDF — malware analysis report

Static analysis result for SHA-256 af4c6534daa12320…

MALICIOUS

PDF

97.6 KB Created: 2021-06-10 20:05:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-02
MD5: c422e73dc7f10b74dfc89ee4c686a2e4 SHA-1: 11c8f23d4fba515e0b845a2ae444349a7b2d5dfe SHA-256: af4c6534daa12320b33f20b71d1ae4214bca9a7f285971d46361228504171b7f
96 Risk Score

Malware Insights

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

This PDF document was flagged as malicious by an ML classifier. The file embeds a large number of external links characteristic of an SEO link farm, many hosted on compromised CMS upload directories. Specific URLs and indicators for this sample are listed in the indicators section.

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://nomylo.ru/uplcv?utm_term=kunkka+support+build PDF link annotation
    • https://homini.eu/wp-content/plugins/formcraft/file-upload/server/content/files/160727c46ebb06---33159917452.pdfIn PDF document text
    • https://www.acptechnologies.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607882e525bf4---97031207580.pdfIn PDF document text
    • http://sskj.pl/userfiles/file/31386853183.pdfIn PDF document text
    • http://pizzeria-millemiglia.de/app/webroot/img/editor/file/99527815957.pdfIn PDF document text
    • http://www.nationaalgolfcongres.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1609865a9cda6b---wedirowuwulolu.pdfIn PDF document text
    • http://www.agrosystem.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160946a7e4ad50---81532509838.pdfIn PDF document text
    • http://aberdeeneyes.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1606cbacf6b2f3---11192615521.pdfIn PDF document text
    • https://sketchup360.vn/wp-content/plugins/super-forms/uploads/php/files/191gpbpj0qsc292qfrbhhnbk62/38510773612.pdfIn PDF document text
    • http://networkinglikepro.com/ckfinder/userfiles/files/32584257674.pdfIn PDF document text
    • http://www.radiopopiatej.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bff641acb34---64932108923.pdfIn PDF document text
    • http://www.linkkorea.co.kr/wp-content/plugins/formcraft/file-upload/server/content/files/16076f22fc2145---puwogadibavewazajesoleno.pdfIn PDF document text
    • https://aulacvn.com/upload/fck/file/zenikexus.pdfIn PDF document text
    • http://allamericannursing.com/userfiles/file/bekigejizituw.pdfIn PDF document text
    • http://www.primalegal.eu/wp-content/plugins/super-forms/uploads/php/files/go61j5srpatcimh2rb0132rjr4/62357747312.pdfIn PDF document text
    • https://aiaciran.org/cache/fck_files/file/98743348533.pdfIn PDF document text
    • https://sipare.com.ar/wp-content/plugins/super-forms/uploads/php/files/u177rr82th9lb25301vp21enrl/nanujuwadujutujaminof.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00013546.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13546 4892 bytes
SHA-256: 279ada8715394edf65bd400ed6905122e9ba60d4b50022ebea9f940633276ab1
font_01_sfnt_off000145d8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x145D8 10972 bytes
SHA-256: a62bc8b5b47b3ee58ea904282a8e5276d70ae1cb64aa04fac29e358e48fefa8d
font_02_sfnt_off00016b36.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16B36 4324 bytes
SHA-256: b50a2106bf82917db0cd3cf88f63c5e8cc3298b343ace5cffc591b35df33d24c