Malicious PDF — malware analysis report

Static analysis result for SHA-256 a87436d065b11146…

MALICIOUS

PDF

70.9 KB Created: 2021-10-03 15:37:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 3c53d008c5d04d86e64116cad0c1c876 SHA-1: 40d0c2250b7064c0403cdc40583a8eff13c4408c SHA-256: a87436d065b1114673bb6a78ecde33b34a319b452fc74c85c6066776b16cb2ed
156 Risk Score

Malware Insights

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

This PDF file was flagged as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous external URLs, many of which are hosted on compromised CMS uploads or disposable domains, suggesting a link farm designed to redirect users to potentially harmful content. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics further supports this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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=pokemon+black+and+white+rom+nds PDF link annotation
    • http://vallovin.it/userfiles/files/notasefobefon.pdfIn PDF document text
    • http://rioairporttransfer.com/ckfinder/userfiles/files/8842688981.pdfIn PDF document text
    • https://anandamsanyal.com/userfiles/file/nuxanozajuturewupe.pdfIn PDF document text
    • http://tuttotop.com/userfiles/files/1192247575.pdfIn PDF document text
    • https://roxracing.eu/userfiles/file/87502006050.pdfIn PDF document text
    • http://designpavelzapletal.cz/files/file/girasikite.pdfIn PDF document text
    • http://www.patricktennis.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613f47c36a268---89224009334.pdfIn PDF document text
    • https://amd-export.com/site/upload/file/33017432408.pdfIn PDF document text
    • http://tfh-filter.hu/_user/file/27212600667.pdfIn PDF document text
    • http://www.fsnn.se/wp-content/plugins/formcraft/file-upload/server/content/files/1612ea55ddf76a---kodojewod.pdfIn PDF document text
    • http://hypotekaprezamestnancov.sk/res/file/bariwezolinofizeterew.pdfIn PDF document text
    • http://steelfurniturecn.com/d/files/57636274595.pdfIn PDF document text
    • https://art-gallery.mn/uploads/files/77849577066.pdfIn PDF document text
    • http://buffagiuseppeinfissi.com/userfiles/files/18917381177.pdfIn PDF document text
    • http://optimumnieruchomosci.pl/uploads/userfiles/files/93068012894.pdfIn PDF document text
    • https://landbondcorten.com/attachment/file/179be8602ee054677d2937995fde4be5.pdfIn PDF document text
    • https://churchosonline.com/wp-content/plugins/super-forms/uploads/php/files/5017aade78e557a6eeabc39a9d4ac5f4/jepekot.pdfIn PDF document text
    • https://isagrinio.gr/userfiles/82427375806.pdfIn PDF document text
    • https://fpcofmacon.com/nbloom/fckuploads/file/6753833985.pdfIn PDF document text
    • http://thegoshow.net/userfiles/file/73340927982.pdfIn 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://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_off0000b050.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB050 10952 bytes
SHA-256: 3c91f6430313698702cc21619fff950c4c73172cb2fa8fa2c7947cba89217738
font_01_sfnt_off0000c991.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC991 17260 bytes
SHA-256: 66d1a890c06a83f8d119fa27bf5b528ac0325146470817135bfa0a27f17de175
font_02_sfnt_off0000f632.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF632 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1