Malicious PDF — malware analysis report

Static analysis result for SHA-256 66a4927d5cef95a3…

MALICIOUS

PDF

91.5 KB Created: 2021-07-20 09:53:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-15
MD5: be52c3eae664ee0193b5329435ce7aac SHA-1: 754f0d8224b1abcb44c5ac1264e486216d97b478 SHA-256: 66a4927d5cef95a363ebd1a7e7284785d8466d3466e796a0d1fef39be990dbb9
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with many URLs pointing to compromised CMS upload directories or disposable hosting. The document body is heavily obfuscated and unreadable, suggesting it's designed to hide its malicious intent rather than convey information.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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 http://toonesk.com/upload/japizazumenoxazijozimi.pdf In PDF document text
    • https://realestateconnect.pro/wp-content/plugins/super-forms/uploads/php/files/8fo3fcv0ri53qfq44d3ovst3e0/13174201800.pdfIn PDF document text
    • http://fundraisingwebsites.com/clients/9/96/963d931f30a9d2280975e71a7f923c96/File/28293191868.pdfIn PDF document text
    • https://estigotours.com/wp-content/plugins/super-forms/uploads/php/files/097cc5d7930ec9dc8666aacc205a29a7/kimikedetisaviginoxix.pdfIn PDF document text
    • http://www.nbrownies.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160ae8924a3626---widugonofamekivotipodupef.pdfIn PDF document text
    • http://www.ncstarim.com.tr/wp-content/plugins/super-forms/uploads/php/files/j8ofkml44rgvu3nq8f5onusuf5/fezobomemuvu.pdfIn PDF document text
    • https://avenirpourtous.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16086b6e329e94---92335029435.pdfIn PDF document text
    • https://congchunghadong.com/uploads/files/3490025807.pdfIn PDF document text
    • http://xn--80akij1ajew.xn--p1ai/wp-content/plugins/formcraft/file-upload/server/content/files/1609adbc73efd1---60215460108.pdfIn PDF document text
    • https://agrachoff.ru/wp-content/plugins/super-forms/uploads/php/files/1d577e8949e2aef481900360953d7a28/69294362637.pdfIn PDF document text
    • http://shinies.ru/img/lib/file/nefenelelatexadetoti.pdfIn PDF document text
    • http://sinproval.it/userfiles/files/16843548959.pdfIn PDF document text
    • http://shelton1961.com/clients/35589/File/vawukigexu.pdfIn PDF document text
    • https://agsposure.org/wp-content/plugins/super-forms/uploads/php/files/b55493d04e9f35f2502495c5690ed9b6/61155914314.pdfIn PDF document text
    • http://marinapogon.pl/upload/file/sumujegajilumosojuni.pdfIn PDF document text
    • http://www.expo-hotel.com/english/wp-content/plugins/formcraft/file-upload/server/content/files/160acbc425e041---29189308853.pdfIn PDF document text
    • http://www.virtualaid.eu/wp-content/plugins/formcraft/file-upload/server/content/files/1609650f445305---18567330604.pdfIn PDF document text
    • http://zabradli-znerezu.cz/userfiles/file/xofipij.pdfIn PDF document text
    • https://k-kompany.ru/wp-content/plugins/super-forms/uploads/php/files/b82401de1691820fc271f887827fb6f9/91833102888.pdfIn PDF document text
    • http://qytbearing.com/upfile/file/gubose.pdfIn PDF document text
    • https://www.getfitcrew.com/wp-content/plugins/formcraft/file-upload/server/content/files/160adc6036a156---xetuwimoruz.pdfIn PDF document text
    • http://verynailscm.com/user_img/file/19480263070.pdfIn PDF document text
    • http://pnmanagementsolutions.in/uploads/31511552343.pdfIn PDF document text
    • https://southtours.com/wp-content/plugins/super-forms/uploads/php/files/9irhrue565q6o23r1vc0s1tqf1/77562374356.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/cv9VXjIrmdE/uplcv?utm_term=the+new+adventures+of+winnie+the+pooh+cleanliness+is+next+to+impossiblePDF 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_off000101f5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x101F5 16764 bytes
SHA-256: 7809b481ca5275cf2404917dca131c7f8d8c27b0a11d1cfc5bfbcda5cea5e26a
font_01_sfnt_off00012dae.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12DAE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000145c5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x145C5 11340 bytes
SHA-256: e588cc5c8d8d05257d3c3e7d8683ca3b6190768c81d4fe33006f623fbfd0ebf4