Malicious PDF — malware analysis report

Static analysis result for SHA-256 c35b7bfe3c949c17…

MALICIOUS

PDF

86.9 KB Created: 2021-08-02 08:47:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 0ef4a27eab2ec660fa2574c1e3aedd23 SHA-1: 20ae89cc9e695600455bd20fe1b4b9db8091a25d SHA-256: c35b7bfe3c949c17593227a843f9b5273ce7d0ed792e9613c9bb9ee55d789319
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was identified as malicious by ML classifiers and ClamAV, indicating a phishing or malware distribution intent. It functions as a link farm, with numerous embedded URLs pointing to compromised websites, likely to lure users into downloading further malicious content or submitting sensitive information. The presence of external URI heuristics and link farm indicators reinforces this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://krisoc.ru/uplcv?utm_term=reading+comprehension+worksheets+7th+grade+multiple+choice PDF link annotation
    • http://hindel-relax.ch/ckfinder/userfiles/files/jojebanojag.pdfIn PDF document text
    • https://www.straightmyteeth.com/wp-content/plugins/super-forms/uploads/php/files/61d9e0a3866b344d6eb5e6f3fa96fc2f/97421566818.pdfIn PDF document text
    • https://alfa-pechati.ru/wp-content/plugins/super-forms/uploads/php/files/4423e4acc9ecf174bc44079ccbe39a09/24809727185.pdfIn PDF document text
    • https://www.gml.de/wp-content/plugins/formcraft/file-upload/server/content/files/160b9bd580c01e---70958084960.pdfIn PDF document text
    • http://www.kzhep.in.ua/wp-content/plugins/super-forms/uploads/php/files/s939mrdv9atvo3rimhbircj2c4/kikebidoralusukanifubax.pdfIn PDF document text
    • https://auf.vn/wp-content/plugins/super-forms/uploads/php/files/0rkqetvksb26cc5qsiqvsbo3k0/vululesusaridaxelepuw.pdfIn PDF document text
    • https://shopabrang.com/images/files/32009951440.pdfIn PDF document text
    • http://ozona.pt/wysiwygfiles/file/21133358415.pdfIn PDF document text
    • https://relaxationplusmn.com/wp-content/plugins/super-forms/uploads/php/files/ea72880f6fa28bf3efadf37d39fd774e/xafikiduterabenedexete.pdfIn PDF document text
    • http://ctnphrae.com/ckfinder/userfiles/files/kobajazudovedevopo.pdfIn PDF document text
    • http://atthaya.com/file_media/file_image/file/lugadigererusaxesijijozu.pdfIn PDF document text
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f533de77e08---39065804227.pdfIn PDF document text
    • http://dabien.co.kr/wp-content/plugins/formcraft/file-upload/server/content/files/16070621116bdf---77364275709.pdfIn PDF document text
    • https://finestblogger.de/wp-content/plugins/super-forms/uploads/php/files/q8mtfjbc0ao4g9i3o5nfccfs7b/37025288099.pdfIn PDF document text
    • http://www.photonics-science.com/ckfinder/userfiles/files/65306117610.pdfIn PDF document text
    • http://medica-brno.com/files/73350861897.pdfIn PDF document text
    • https://omomediacion.com/wp-content/plugins/super-forms/uploads/php/files/5ebd96685bd6e22e382f553c43d2e0c8/90028062270.pdfIn PDF document text
    • https://balticstroy.com/uploads/files/tapobewafafugifowunegif.pdfIn PDF document text
    • https://study-go.info/wp-content/plugins/super-forms/uploads/php/files/183e5cb7c9a40173befe9098a6002f2c/mimon.pdfIn PDF document text
    • http://alphasigmaoverseas.com/userfiles/file/92564651972.pdfIn PDF document text
    • https://xn----8sbaavnccwq4am.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/8e7dd64aa7e570935f11b6950b791583/9583013612.pdfIn PDF document text
    • http://www.loockuniformes.com.br/home/wp-content/plugins/formcraft/file-upload/server/content/files/16093b3dc87415---sagiwutego.pdfIn PDF document text
    • https://www.lorenzofranzone.it/wp-content/plugins/super-forms/uploads/php/files/8103435f2c503522e6004bb117f76ed1/lojumapojiwi.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_off0000ef15.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF15 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0001072c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1072C 11336 bytes
SHA-256: 827bbddd0d0644e6515626f19f7309796491826aaf9fcd4dd4af5bbd1ec013b6
font_02_sfnt_off0001217f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1217F 16836 bytes
SHA-256: 7c0db42e323a4bb82b3f680eee3b7377780be571f064af492370d64a2aa7fd91

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