Malicious PDF — malware analysis report

Static analysis result for SHA-256 a7c74198150788ac…

MALICIOUS

PDF

82.5 KB Created: 2021-09-05 22:58:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-29
MD5: 124447d03e422ad7a112c9635b5bf9a2 SHA-1: 0e4afd9dcfc24a29348731b1c0b19ea7d1260398 SHA-256: a7c74198150788ac2791d451b583c1b00cc210533f9524952c7c3a7887c9ceb5
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, with heuristics indicating it functions as a link farm. Multiple URLs extracted from the document point to compromised WordPress sites, suggesting an attempt to lure users to external resources. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but containing embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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://purebodycare.courses/wp-content/plugins/super-forms/uploads/php/files/imnp2nv3fb5e97089422p967m9/dukanidisido.pdf In PDF document text
    • https://emergent-partners.com/wp-content/plugins/formcraft/file-upload/server/content/files/160acf478493c3---65764044054.pdfIn PDF document text
    • https://www.kiteschule-kiel.de/wp-content/plugins/formcraft/file-upload/server/content/files/160de7964cf7ba---65572095352.pdfIn PDF document text
    • https://www.quatainvestimentos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1611ff4d5358eb---74603104273.pdfIn PDF document text
    • https://spectrumohio.com/wp-content/plugins/super-forms/uploads/php/files/0c2db7e1391809f0779a412c55bdce9a/zetagopebafamigulo.pdfIn PDF document text
    • http://chromatographvials.com/d/files/95051656620.pdfIn PDF document text
    • https://nuregio.de/wp-content/plugins/formcraft/file-upload/server/content/files/161120bd6a5d04---46973118907.pdfIn PDF document text
    • https://nuttydog.hu/ckfinder/userfiles/files/98666983764.pdfIn PDF document text
    • https://phatgiaolongan.com/upload/ckupload/files/36318516396.pdfIn PDF document text
    • http://abnicum.com/files/file/zogabulag.pdfIn PDF document text
    • https://dwitunggaljaya.com/sitefiles/file/rumasofurubobene.pdfIn PDF document text
    • http://tuyothuyluc.vn/webroot/img/files/juxaxizosojuwowizuroz.pdfIn PDF document text
    • http://marcobernini.it/userfiles/files/toxekotada.pdfIn PDF document text
    • https://sakitonus.ru/wp-content/plugins/super-forms/uploads/php/files/b61fbc6413fdcac950741c2124e4e6b1/gigem.pdfIn PDF document text
    • https://tkpmission.org/wp-content/plugins/formcraft/file-upload/server/content/files/1610c0e229f85a---40018243993.pdfIn PDF document text
    • http://hotelstrack.com/bot/ckfinder/uf/files/22921962642.pdfIn PDF document text
    • https://deewo.de/wp-content/plugins/formcraft/file-upload/server/content/files/160ae0f02543cb---4774556951.pdfIn PDF document text
    • http://myphamlulanjina.com/upload/files/95164350914.pdfIn PDF document text
    • https://rfcorporation.net/wp-content/plugins/super-forms/uploads/php/files/fb7c5f64fae56d4675f65d25509ca45a/23264676271.pdfIn PDF document text
    • http://ylpqzl.com/ckfinder/userfiles/files/19696211597.pdfIn PDF document text
    • https://chamsocmuihong.com/wp-content/plugins/super-forms/uploads/php/files/i6s2gij352i1k898068teuucv8/57877459493.pdfIn PDF document text
    • https://delaneyllc.cfonewsletter.com/ckfinder/userfiles/files/14193638290.pdfIn PDF document text
    • https://bettenbaehren.de/wp-content/plugins/formcraft/file-upload/server/content/files/1606d1a3caebb5---45950683040.pdfIn PDF document text
    • http://arcdesantmarti.com/biocop/Images/images-editor/file/36999852601.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BvfzZFkJO3s/uplcv?utm_term=periodic+trends+worksheet+answerPDF 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_off0000dba7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDBA7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f3b9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF3B9 18680 bytes
SHA-256: b55cf2193ca9750448821dea124a3e6c22bfe4e7191623c1c63e9c4429c65bc3
font_02_sfnt_off0001249b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1249B 10600 bytes
SHA-256: 808e42dc00d527ef3bcf21ea9b31e3ed3e185ce58d18f7725a5664fa7f12985a