Malicious PDF — malware analysis report

Static analysis result for SHA-256 f77c82bb539a7997…

MALICIOUS

PDF

135.4 KB Created: 2021-07-04 08:20:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: 6e2fbd1d4dce11fecf0cb6210f90e9f4 SHA-1: 25a4d48cc06349e2952084f557ca6a2aeac47851 SHA-256: f77c82bb539a79975b0a943d4316acf3adcb83cff3a53da2690bba61db3a225c
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple external URLs, some hosted on compromised CMS uploads. The document body is heavily obfuscated, preventing a clear understanding of its specific lure, but the overall structure and URL distribution suggest a phishing or malicious content distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9925

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 http://parejalecaros.com/adjunto/upload/fck/files/zutanisofexekejekusugij.pdf In PDF document text
    • https://www.axelendinggroup.com/wp-content/plugins/super-forms/uploads/php/files/ffa6e8e39473e4dad69cb0b2e0e3ea26/87419113766.pdfIn PDF document text
    • http://nguyenthaotech.com/upload/files/nagof.pdfIn PDF document text
    • http://supermarketdv.ru/files/file/68793420680.pdfIn PDF document text
    • http://diakmelo.hu/ckfinder/userfiles/files/lupoxitupo.pdfIn PDF document text
    • https://www.adelaarenergy.com/wp-content/plugins/super-forms/uploads/php/files/7e9l3929rtbh1l18dtsr0q195p/84044658623.pdfIn PDF document text
    • http://animalscipublisher.com/files/upfiles/file/50815826793.pdfIn PDF document text
    • http://www.ambredore.com/wp-content/plugins/formcraft/file-upload/server/content/files/16091ccfcac5e9---depipobotufobufer.pdfIn PDF document text
    • http://absolutelyneon.com/userfiles/file/mulujamepu.pdfIn PDF document text
    • https://mercedesmazo.es/wp-content/plugins/formcraft/file-upload/server/content/files/160a40fc7ba58c---8269985065.pdfIn PDF document text
    • http://adamlegal.com/userfiles/file/88647864451.pdfIn PDF document text
    • http://www.masozilina.sk/ckfinder/userfiles/files/kolufopilerefukumojagagi.pdfIn PDF document text
    • https://amartzon.store/wp-content/plugins/super-forms/uploads/php/files/25a954ccffcc26b7d7efe1842cba0c40/mezeveduvo.pdfIn PDF document text
    • https://fobiy.net/wp-content/plugins/super-forms/uploads/php/files/785040587cdc0b40a13ed9d546ae8a8a/88635172108.pdfIn PDF document text
    • http://artospace.com/pics/file/lobavikegax.pdfIn PDF document text
    • http://oio.cn/uploadfiles/files/48001826542.pdfIn PDF document text
    • http://www.opencalgary.org/wp-content/plugins/formcraft/file-upload/server/content/files/160c6dec85d36d---38745382025.pdfIn PDF document text
    • https://cleaner.pl/userfiles/file/gezedarebulanivujumu.pdfIn PDF document text
    • https://g3az.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609a57938861a---58984456615.pdfIn PDF document text
    • http://archgeo-leszno.pl/uploads/userfiles/files/lijolanalapojomelon.pdfIn PDF document text
    • http://nek.ua/wp-content/plugins/formcraft/file-upload/server/content/files/160bf6b40690ae---tazixiruwadojelovevep.pdfIn PDF document text
    • https://eclipsetheaters.com/wp-content/plugins/formcraft/file-upload/server/content/files/16071bd3a09841---76555993518.pdfIn PDF document text
    • https://psychotherapie-dr-albrecht.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607d9569d5701---ropopojujefubivaw.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1xuhb7AK25c/uplcv?utm_term=modern+cryptography+theory+and+practice+pdfPDF 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_off0001ad7a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1AD7A 18448 bytes
SHA-256: 3e4aff4c4818a53b05b03eb5d4fbe6fb631f09c9f73dbc46f291606ecf288033
font_01_sfnt_off0001dd8a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1DD8A 10792 bytes
SHA-256: 717073850ab8480b850f5a401dff18f78ae98378fc3592b0b37b159aab4332a9
font_02_sfnt_off0001f620.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1F620 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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