Malicious PDF — malware analysis report

Static analysis result for SHA-256 a457c5e83f36b83a…

MALICIOUS

PDF

81.3 KB Created: 2021-09-16 07:04:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 2156ac775fa9e765ef02abb4a494dd88 SHA-1: 844d24f4d564cb54aa1d59c9a3bd9e30fc269c80 SHA-256: a457c5e83f36b83ac3c09394a105d671e18d6ac75d2add0dd1360404a9596b62
156 Risk Score

Malware Insights

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

The file was detected by ClamAV as Pdf.Phishing.Trojan and an ML classifier flagged it with high confidence. Heuristics indicate it functions as a link farm, pointing to compromised WordPress upload storage and other disposable hosting. The embedded URLs suggest a phishing or malware distribution attempt, likely initiated via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9917

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 http://www.biogreeno.com/cms/ckfinder/userfiles/files/35252947611.pdf
    • http://geotersrl.it/file/81825465823.pdf
    • http://aybar-gallery.com/userfiles/files/kuxenirimodomiditen.pdf
    • http://madurastones.com/userfiles/file/69190307608.pdf
    • https://pikhospital.com/ck_uploads/uploads/files/28004609027.pdf
    • http://digitalqwerty.com/ckfinder/userfiles/files/54217981675.pdf
    • https://muzeumkonstancina.pl/attachments/file/35853749953.pdf
    • http://erodiertechnik-wenzel.de/userfiles/file/zemuzi.pdf
    • http://rbc-bezorgdiensten.nl/upload/rezewekamakapiwexafo.pdf
    • https://jin-hung.com/userfiles/file/bivaxosi.pdf
    • http://audiomaster.se/wp-content/plugins/formcraft/file-upload/server/content/files/161340383b1085---jijokukew.pdf
    • https://classconnbio.com/img-jacson/files/58128060807.pdf
    • http://zeci.nl/im/image/subawupelapotubagujojox.pdf
    • http://begues.mobi/userfiles/file/sagulefufe.pdf
    • http://status.cz/UserFiles/File/nosixoki.pdf
    • http://ikhmongol.mn/ckfinder/userfiles/files/81409643673.pdf
    • https://www.cir.cloud/wp-content/plugins/formcraft/file-upload/server/content/files/161428fec1e8dd---45496897782.pdf
    • https://suacuachuyennghiep.com/uploads/files/golomelitatuk.pdf
    • https://www.gpaci.org.br/cms/ckfinder/userfiles/files/31998338240.pdf
    • http://www.louthadventures.ie/wp-content/plugins/formcraft/file-upload/server/content/files/161306586e6fae---zejabigifowapami.pdf
    • http://paramountswimwear.com/userfiles/files/96944224414.pdf
    • http://ainut.fi/userfiles/file/bisulejinazil.pdf
    • https://leise.ru/admin/ckfinder/userfiles/files/dudagawabobojudiguta.pdf
    • https://alasclub.gr/neuro/ckfinder/userfiles/files/kodisekixaxak.pdf
    • http://rucodelniza.ru/userfiles/file/44898336451.pdf
    • http://vegasoft.hr/wp-content/plugins/formcraft/file-upload/server/content/files/161305b7eabfd8---43769624128.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1KS0DP0cxss/uplcv?utm_term=delete+snapchat+filter
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d9fd.bin
e785b79286dc1319cef09df3497e844393884c399828430e95bd80403139347f
pdf-font-stream PDF embedded font (sfnt) at offset 0xD9FD 17800 bytes
font_01_sfnt_off00010787.bin
6fc89e5090dbbde37cc81d483846291dcb9711da8126b7f6e7eec9f3aaef8fe2
pdf-font-stream PDF embedded font (sfnt) at offset 0x10787 10456 bytes
font_02_sfnt_off00011f3b.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x11F3B 16792 bytes