Malicious PDF — malware analysis report

Static analysis result for SHA-256 4123dfba37c3d2d2…

MALICIOUS

PDF

90.8 KB Created: 2021-07-22 09:54:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 91260ea6e88c095f8e236a95afdc033f SHA-1: 684dbef4538e84e747ce34b2f6bbc581f64e04fc SHA-256: 4123dfba37c3d2d22232361c9919348c07ef21810c9b8bcc7253903f8db845d4
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by ClamAV and an ML classifier as malicious, specifically as a phishing trojan. It contains a link farm pointing to compromised WordPress uploads and other disposable hosting, suggesting an attempt to lure users to external sites. The document body is heavily obfuscated and appears to be non-readable content generated by wkhtmltopdf, rather than user-facing text.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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://brezov-gaj.si/uporabnik/file/9351683737.pdf In PDF document text
    • http://juliesfundforkids.com/clients/d/d6/d6f17a7a4e9d342a12f8f8eeddb80b2d/File/37484672556.pdfIn PDF document text
    • https://djennebeads.com/nbloom/fckuploads/file/34720047741.pdfIn PDF document text
    • https://cape-electronics.com/media/file/vizosizobagoro.pdfIn PDF document text
    • http://apsara.ru/userfiles/file/46977073325.pdfIn PDF document text
    • https://promocionesnma.com/wp-content/plugins/super-forms/uploads/php/files/4df41e87fcbcb0d8ba033ef1cc465a18/mudomamisalutamazevap.pdfIn PDF document text
    • https://reflexlighting.com/wp-content/plugins/super-forms/uploads/php/files/59627253fa05ee1c0409426495ba37f3/xakowab.pdfIn PDF document text
    • https://brod-plovdiv.com/images/ribuxejuvugo.pdfIn PDF document text
    • https://quatcongnghieput.com/uploads/files/tixuluj.pdfIn PDF document text
    • https://jfefood.com/wp-content/plugins/super-forms/uploads/php/files/958056020a7a088be7dbd1974169d341/jorimowonanabato.pdfIn PDF document text
    • http://itaindustrial.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608a722e0250c---nezumutaboxot.pdfIn PDF document text
    • https://vaytieudungtragop.com.vn/wp-content/plugins/super-forms/uploads/php/files/jmkj31emgfa1jcdkg4i74p2qrc/tusenawezib.pdfIn PDF document text
    • https://humanistbeauty.com/wp-content/plugins/super-forms/uploads/php/files/ov8cq9rk9q3kruraj3kr8o6pr0/65608789493.pdfIn PDF document text
    • https://www.higher-energy-trampolineclub.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607912fa56a65---vewaxadirew.pdfIn PDF document text
    • https://chilegastronomia.cl/uploads/userfiles/files/sixevojeretodibubak.pdfIn PDF document text
    • https://www.reparaciondebomba.com.ar/wp-content/plugins/super-forms/uploads/php/files/1k0oafh3ae3370k0viq41ehi56/86296589413.pdfIn PDF document text
    • https://law.myvzl.com/wp-content/plugins/super-forms/uploads/php/files/fldv6d708i4edn8dmc46dj76i7/bajewokosukawimeronasuz.pdfIn PDF document text
    • http://westboroughhigh76.com/clients/b/bc/bc4984db1d461a603911d7e4814e3e59/File/39347583053.pdfIn PDF document text
    • https://ifacemount.com/wp-content/plugins/super-forms/uploads/php/files/ngpcjih0s6gpcuaf0cmf2fuegj/fupakesubu.pdfIn PDF document text
    • http://www.qookspot.kitchen/wp-content/plugins/formcraft/file-upload/server/content/files/1607afa48446b3---litunadilazemipomuxej.pdfIn PDF document text
    • http://falerisztika.hu/tmp/79835618025.pdfIn PDF document text
    • https://www.mclarenpress.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607446885ca9b---boduvepefuk.pdfIn PDF document text
    • http://garmagostaran.com/Upload/file/60412995484.pdfIn PDF document text
    • http://phuongsen.com/img-chamthi/files/51780962186.pdfIn PDF document text
    • https://frasertechno.com/wp-content/plugins/formcraft/file-upload/server/content/files/16082fdea8c22f---talaraki.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=properties+and+characteristics+of+soundPDF 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_off00010257.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10257 10772 bytes
SHA-256: e7ceac938a57b5e6e9e33de529f086fac728375f479c1ce126eb754559312ab9
font_01_sfnt_off00011b10.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11B10 16136 bytes
SHA-256: 27ff8477d1333fb9b418f598b0a68e3e7949cfe288f8cd38435c0861ef8a4aef
font_02_sfnt_off000144b7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x144B7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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