Malicious PDF — malware analysis report

Static analysis result for SHA-256 655f270544ace7e7…

MALICIOUS

PDF

81.4 KB Created: 2021-09-19 01:56:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: f3238dac611e92e3c955881203b0b59b SHA-1: ab240ed919d29bfef67921566a0bc6079fe91dfd SHA-256: 655f270544ace7e7a1894bea2db0d4ea04606eedc0896b78dd98db0ffb1aa598
146 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was identified as malicious by ClamAV and an ML classifier, exhibiting characteristics of a callback phishing lure. It contains numerous embedded URLs pointing to PDF files hosted on various domains, suggesting a link farm or redirection mechanism. The document body is heavily obfuscated, but the presence of PDF_URI and PDF_SEO_DISPOSABLE_LINK_FARM heuristics indicates a pattern of linking to external, potentially malicious, content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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
  • 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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • 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://pixomot.ru/uplcv?utm_term=android+build+info PDF link annotation
    • http://jumpstart.mobi/userfiles/file/revasoze.pdfIn PDF document text
    • http://stroynerud-sm.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1613693d60db5d---84245896999.pdfIn PDF document text
    • http://toflight.mobi/attachment/ckeditor/files/5b1882b2757474acc40e6965fba2c543.pdfIn PDF document text
    • https://brakos.it/file/jifalegusimelulukabu.pdfIn PDF document text
    • https://onwater.my/uploads/file/46758942843.pdfIn PDF document text
    • http://firewheels.pe/userfiles/file/15258409587.pdfIn PDF document text
    • http://dogoxuavanay.vn/uploads/files/difunisuzoba.pdfIn PDF document text
    • http://yushendesign.com/images_fck/file/1631377855.pdfIn PDF document text
    • https://tattica.byespresso.com/app/webroot/files/upload/files/18130623994.pdfIn PDF document text
    • http://www.mkkdigital.pt/wp-content/plugins/formcraft/file-upload/server/content/files/1613432c6d3d81---kufimanepo.pdfIn PDF document text
    • http://chinajnbt.com/images/upload/File/wobufenumigemafapujusutux.pdfIn PDF document text
    • http://recko.ru/ckfinder/userfiles/files/30318773499.pdfIn PDF document text
    • http://burattinojatek.hu/userfiles/file/gifoxabotolarega.pdfIn PDF document text
    • http://xn--80aadcnaeutgftohcogh8i8dsc.xn--p1ai/pict/file/bipumexam.pdfIn PDF document text
    • http://hidramaco.com/files/files/88636319206.pdfIn PDF document text
    • https://global-brand.net/userfiles/files/fuvovonosikenu.pdfIn PDF document text
    • http://phupmirpol.pl/userfiles/file/67113282297.pdfIn PDF document text
    • http://guidesdugrandlarge.fr/images/import/file/5226838664.pdfIn PDF document text
    • https://adminico.nl/userfiles/file/63728427186.pdfIn PDF document text
    • http://tischlerei-schlusche.de/sites/default/files/file/54335912736.pdfIn PDF document text
    • http://xn--80aiddhbkcq5bcaz.xn--p1ai/upload/files/towopemo.pdfIn PDF document text
    • http://vigova.com/Images_upload/files/46333325229.pdfIn PDF document text
    • http://euroteam.vn/ckfinder/userfiles/files/zanebujekufadujidon.pdfIn PDF document text
    • http://antifftech.com/uploadfile/file///2021091104484279.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_off0000ddde.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDDDE 10008 bytes
SHA-256: ac66a3f9beb6bed44c840688c542fe6f953fe02b4ae536977bc0c9cb152a30be
font_01_sfnt_off0000f40c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF40C 16964 bytes
SHA-256: 3aea9b417e8ff6375f7610d3298eaafdf7e6117e9aa4f7f019edd7028ce2332e
font_02_sfnt_off0001200b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1200B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1