Malicious PDF — malware analysis report

Static analysis result for SHA-256 b51a906135957e2f…

MALICIOUS

PDF

80.9 KB Created: 2021-09-11 19:32:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 4c1c95b96058d4b0701158b7b265a87f SHA-1: 2af5be5eac7969178b3ee6d8b942b04b04709890 SHA-256: b51a906135957e2f191ca328894f010d4c534e46906ccc8018e09f13c87e1a18
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous embedded URLs that point to a variety of external websites. Several heuristics indicate that these URLs are part of a link farm, with some pointing to compromised CMS upload storage and others to disposable hosting. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery through these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9911

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://irlanc.ru/uplcv?utm_term=back+buttons+app PDF link annotation
    • http://luijkzonwering.nl/image/file/rezaxajesoxeruvunoxikumuf.pdfIn PDF document text
    • https://handientu.vn/userfiles/file/nunirekodakudabejuwod.pdfIn PDF document text
    • http://worldsocialistpartyindia.org/ckfinder/userfiles/files/10958620206.pdfIn PDF document text
    • http://ohmamakitchen.com/uploads/files/vunilipawiz.pdfIn PDF document text
    • https://biographiewerkstatt-singer.de/userfiles/file/jiniweboguga.pdfIn PDF document text
    • http://findingthegrey.com/userfiles/file/92539356568.pdfIn PDF document text
    • http://rosabaum.de/web/editor/files/gexosemajibiwufor.pdfIn PDF document text
    • http://bjxbw.cn/userfiles/file/mefaro.pdfIn PDF document text
    • http://kielcenoca.pl/files/file/15348329854.pdfIn PDF document text
    • http://mygotour.com/FileData/ckfinder/files/20210907_EB45F12ADA6BC847.pdfIn PDF document text
    • https://testpensija.bankai.lv/ckfinder/userfiles/files/pezuzow.pdfIn PDF document text
    • http://www.trisad.kz/ckfinder/userfiles/files/43656910695.pdfIn PDF document text
    • http://ukonlinedirect.com/userfiles/files/5377094775.pdfIn PDF document text
    • https://yournew.site/wp-content/plugins/super-forms/uploads/php/files/rlu41ptl1de96f2frcfc176k34/lotavuvajodida.pdfIn PDF document text
    • https://pbchistoryonline.org/uploads/file/83916616484.pdfIn PDF document text
    • https://texasbordervolunteers.org/userfiles/file/86136481076.pdfIn PDF document text
    • https://mywayrtk.com/userfiles/file/71690609181.pdfIn PDF document text
    • http://joshuadacosta.com/wp-content/plugins/formcraft/file-upload/server/content/files/16135071398f93---25207310419.pdfIn PDF document text
    • https://traiteur-troyes-mariage-buffet-aube-10.blaisot-traiteur.fr/ckfinder/userfiles/files/fojuwufofugo.pdfIn PDF document text
    • http://coumert.com/images/file/33190117093.pdfIn PDF document text
    • http://bridgesonthepark.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c2a915cf9c---zavowuxivojigowomi.pdfIn PDF document text
    • https://birotex.rs/images/files/27013941755.pdfIn PDF document text
    • http://vp-dmsh.ru/admin/ckfinder/userfiles/files/sipufetagus.pdfIn PDF document text
    • http://ciccioinpentola.com/userfiles/files/xofudajikifolepopot.pdfIn PDF document text
    • http://lamorenj.com/userfiles/file/xaduvokufogoparuf.pdfIn PDF document text
    • https://www.booster-p.com/wp-content/plugins/formcraft/file-upload/server/content/files/16133ea2bd2a28---sinijone.pdfIn PDF document text
    • http://arrhythmiaclinic.com/userfiles/file/20210907003821.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_off0000d9a5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9A5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f1bc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1BC 10380 bytes
SHA-256: b7f52cd93cfaadb4af1f0ff8617bb7d206e700cd350fecc0a6f97cb134b43aa3
font_02_sfnt_off0001093c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1093C 17328 bytes
SHA-256: d85337c11b75f056ba2a4195cad77e19a299b6b8913417d28f1470c4f60ba223