Malicious PDF — malware analysis report

Static analysis result for SHA-256 86d359c43259cf9b…

MALICIOUS

PDF

83.6 KB Created: 2021-10-05 14:38:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 79b42e58b53c69085b687b06831f67f5 SHA-1: 90eb0fff2994b001864949b4804d4faf5ddd5059 SHA-256: 86d359c43259cf9bd14c41b997b7ed0c5ce364e45da3e6a7151879fbf1d3416f
196 Risk Score

Malware Insights

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

The sample is identified as malicious by ML classifiers and ClamAV, with heuristics indicating it's a link farm and a browser extension installation lure. The document body is heavily obfuscated, but the presence of numerous URLs pointing to potentially compromised or disposable hosting suggests a phishing or malware distribution attempt. The primary goal appears to be tricking the user into downloading and installing a malicious browser extension or update.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Browser extension / update installation lure high SE_BROWSER_INSTALL_LURE
    Document tells the user to install a browser extension, plugin, viewer, or browser update to view content — a common social-engineering path for credential theft and malware installation
  • 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://coretry.ru/uplcv?utm_term=what+is+the+importance+of+heterotrophs+and+decomposers+in+an+ecosystem PDF link annotation
    • http://kht.civilkozpont.hu/uploads/file/lutezizijexo.pdfIn PDF document text
    • http://centroolosprato.it/userfiles/files/2009420510.pdfIn PDF document text
    • http://ccsl.asia/files/kafunivutidowavaworuzuzo.pdfIn PDF document text
    • http://numere-mopede.ro/mm/file/85648281959.pdfIn PDF document text
    • http://allergya.news-read.com/upload/files/6114186847.pdfIn PDF document text
    • https://www.luxboss.com/ckfinder/userfiles/files/17273674361.pdfIn PDF document text
    • https://quangcaowebsite.vn/uploads/files/55567733712.pdfIn PDF document text
    • https://etest.vn/app/webroot/uploads/files/3046732390.pdfIn PDF document text
    • http://buyo-g.net/userfiles/file/80724911698.pdfIn PDF document text
    • http://www.thebetterinsurance.com/wp-content/plugins/formcraft/file-upload/server/content/files/16142b25e1f6af---wakowijadaforevonefukob.pdfIn PDF document text
    • http://eske.hu/wp-content/plugins/formcraft/file-upload/server/content/files/161322fe7043d2---43057725589.pdfIn PDF document text
    • http://bartuceviri.com/userfiles/file/bekutoza.pdfIn PDF document text
    • http://www.jamesbgriffinlaw.com/wp-content/plugins/formcraft/file-upload/server/content/files/1615890466262b---zesegopofawawitis.pdfIn PDF document text
    • http://hebammenglueck.de/ckfinder/userfiles/files/pujofidugajazaxatax.pdfIn PDF document text
    • http://runo34.ru/attachments/file/jegasaxatarulogil.pdfIn PDF document text
    • http://alacarte-husum.de/userfiles/file/76807101258.pdfIn PDF document text
    • https://bakotech.at/uploads/ckeditor/files/ramogivoxo.pdfIn PDF document text
    • http://fusen-es.info/yamituki-n/uploads/files/22425652851.pdfIn PDF document text
    • http://learnazia.com/fck/imagesfile/giragarired.pdfIn PDF document text
    • http://lotuscourtpune.com/wp-content/plugins/super-forms/uploads/php/files/676613876e77273fdd907d65841a1509/pavenunipudegilamafojetu.pdfIn PDF document text
    • http://happyland-nsk.net/ckfinder/userfiles/files/34273656558.pdfIn PDF document text
    • https://heritagelogs.com/wp-content/plugins/super-forms/uploads/php/files/rn88c0mn2g6chn0v86b6svlo23/jujizatejuvanipu.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_off0000dfc3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFC3 10948 bytes
SHA-256: 0739f9faa88d737683eff8a826a7d2f44320f2be1e5f25d198ccabd9fdc20ad1
font_01_sfnt_off0000f906.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF906 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011118.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11118 18200 bytes
SHA-256: ffd2b738158e9a8221fa1966e64a860223aea58ff5f8396f296c08d6a6245236