Malicious PDF — malware analysis report

Static analysis result for SHA-256 8c85383fe0e85900…

MALICIOUS

PDF

84.1 KB Created: 2021-09-20 21:57:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 77f870a97617f9c642a77b19ab63c179 SHA-1: 1c4ce258fd74d5463fc65706302049cb5490a37c SHA-256: 8c85383fe0e85900d5bdcec67e17a2aafe89ebb2c5521e8c2fd3051e3cb924de
156 Risk Score

Malware Insights

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

This PDF was flagged by multiple heuristics as a link farm, with many embedded URLs pointing to potentially compromised or disposable hosting. The ML classifier and ClamAV also strongly indicated maliciousness, specifically classifying it as a phishing trojan. The document body is heavily obfuscated and unreadable, providing no direct content, but the presence of numerous external links suggests an attempt to redirect users to malicious sites.

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
  • 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://directorvincentchow.com/fck_filemanager_upload/file/88791279006.pdf In PDF document text
    • https://raguvosbaldai.manovonia.lt/images/files/55420384529.pdfIn PDF document text
    • http://cozycornerexpress.com/uploads/files/pawexeg.pdfIn PDF document text
    • https://gruntbudowa.pl/files/file/32235165119.pdfIn PDF document text
    • http://cachnhietcacham.vn/Images_upload/files/tarapuzatirosagezaf.pdfIn PDF document text
    • https://castilloexterior.es/ckfinder/userfiles/files/57731896448.pdfIn PDF document text
    • https://amigo-shop.105h.net/upload/files/zisofolagavezipabekunez.pdfIn PDF document text
    • http://hasomedia.com/userfiles/file/fimulo.pdfIn PDF document text
    • http://etalentlink.com/uploadfile/file///2021091818043756.pdfIn PDF document text
    • http://esrafisek.com/images_upload/files/66710567591.pdfIn PDF document text
    • https://intersat.lv/files/file/67113637875.pdfIn PDF document text
    • http://pokeocncafe.com/uploads/files/2820275355.pdfIn PDF document text
    • https://larrialdiak.es/files/galeria/files/finobawarorojaboxomopax.pdfIn PDF document text
    • http://soft-pro.hr/upload/datoteke/97451781997.pdfIn PDF document text
    • http://sweed-trans.eu/ckfinder/userfiles/files/95206482477.pdfIn PDF document text
    • http://kerrya.com/ckfinder/userfiles/files/65730821864.pdfIn PDF document text
    • https://monarchwinemerchants.com/wp-content/plugins/super-forms/uploads/php/files/48eee21a556a528a0146a8ef00388040/sirigak.pdfIn PDF document text
    • https://artsketch.ru/wp-content/plugins/super-forms/uploads/php/files/09bc032e09750bb12a2f363320554068/ranezexokimavadi.pdfIn PDF document text
    • https://sapporomn.com/userfiles/files/fogij.pdfIn PDF document text
    • http://www.niziointerior.pl/upload/file/57981559385.pdfIn PDF document text
    • https://tutorsbureau.net/userfiles/file/zozekukinoxa.pdfIn PDF document text
    • https://affordans.com/ckfinder/userfiles/files/49824266126.pdfIn PDF document text
    • https://zazilha.com.mx/wp-content/plugins/super-forms/uploads/php/files/2effaddee6252461072a7f88bbc30eae/gifiborivutus.pdfIn PDF document text
    • http://discoveryenglish.org/wp-content/plugins/formcraft/file-upload/server/content/files/16141291987d82---73130168420.pdfIn PDF document text
    • http://dyccpharma.com/upload/files/57797779064.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/zMnd8XtcwSM/uplcv?utm_term=bcmon+no+rootPDF link annotation
    • 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_off0000e348.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE348 9844 bytes
SHA-256: d60a7992828667300080c28d17cbdd97876677091e5fc79644e7ff2f8a0ebb30
font_01_sfnt_off0000f8e0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF8E0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000110f2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x110F2 19164 bytes
SHA-256: 05a09408fda56a0606c2769441ea5cc4eb8a9b6c8a0aa93a8b04f0a48f240d03