Malicious PDF — malware analysis report

Static analysis result for SHA-256 91c7a74bacbb3d43…

MALICIOUS

PDF

77.4 KB Created: 2021-06-09 23:35:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: 388956507e5a7ee20fd9c3438f1bc971 SHA-1: 80a5dc64cb2006aeb109f59df43f80d497d50c67 SHA-256: 91c7a74bacbb3d43eaf653f0658686ba9c317500c57a6dbbfcdfe41fd4dcf568
96 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many pointing to compromised WordPress upload directories, indicating it functions as a link farm. The ML classifier strongly identified this PDF as malicious. The primary purpose appears to be directing users to potentially malicious or phishing content hosted on compromised websites.

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://smidgel.ru/uplcv?utm_term=118+elements+name+with+symbols PDF link annotation
    • https://aquaticlandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081a33b0352a---vezalejawinaridujuxar.pdfIn PDF document text
    • http://veronicanealhome.com/wp-content/plugins/formcraft/file-upload/server/content/files/2/160a5dfcd86d75---24731131697.pdfIn PDF document text
    • https://www.prestigeautobody.com.au/wp-content/plugins/super-forms/uploads/php/files/ac1b7cf4d3256f0bc8db5e9983a4e214/gebigumobabo.pdfIn PDF document text
    • https://majorsagilekvaros.hu/uploads/file/91764534111.pdfIn PDF document text
    • http://n-production.com/upload/fckeditor/file/62488780120.pdfIn PDF document text
    • https://daismene.it/file/vimudawokowakefakunamokup.pdfIn PDF document text
    • http://aquamedia.cn/ckfinder/userfiles/files/25050705790.pdfIn PDF document text
    • https://n95america.com/wp-content/plugins/super-forms/uploads/php/files/465caefdc4939c6b1a1cb949a90b3c66/mupidijemanavovew.pdfIn PDF document text
    • https://fiambreszav.com/wp-content/plugins/super-forms/uploads/php/files/40a5fb6bc8189b064d0cae1687b00f3d/xuvajumo.pdfIn PDF document text
    • http://www.dj-csnl.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160844b6cc4c9d---14157611245.pdfIn PDF document text
    • https://growlocals.com/wp-content/plugins/super-forms/uploads/php/files/4cb64c37f708283701f174d1b8a89245/57157325779.pdfIn PDF document text
    • https://www.sacproblemleri.com/wp-content/plugins/formcraft/file-upload/server/content/files/160af9904741a6---96432564826.pdfIn PDF document text
    • https://hmjrgoldhockey.org/wp-content/plugins/super-forms/uploads/php/files/f3f9263704f1038b845480190011165f/xuvazosesugexexad.pdfIn PDF document text
    • http://fygl.net/uploads/file/310431022887.pdfIn PDF document text
    • https://malimbe.africa/wp-content/plugins/super-forms/uploads/php/files/e80c52b2f4185c914fe9a064119d8437/jobavoninugoditeb.pdfIn PDF document text
    • http://www.next-conseil.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160746b0c96bfc---76305536724.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_off0000f160.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF160 5312 bytes
SHA-256: a2a36e7cf7a871515faf7d8dc63a868d77e42af430a7cbfc9ae8dbad287581df
font_01_sfnt_off00010363.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10363 11072 bytes
SHA-256: 8619be72fcc766412d0afe0664e08eb8a745e9b288beeb36ecfdd7811c2b8515