Malicious PDF — malware analysis report

Static analysis result for SHA-256 813bb441b41784b4…

MALICIOUS

PDF

79.9 KB Created: 2021-09-20 13:10:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 3454a4125c5e9e271ea01ad05450ab4f SHA-1: 34ea0b04e347723d9c853ee26ebf2e6ebecd07b2 SHA-256: 813bb441b41784b41eef198357b4098cbdfd63111e2a3d039356a782011f4c30
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, many pointing to compromised WordPress uploads and disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or distributing further malware. Although no scripts were explicitly extracted, the PDF structure and link farm behavior are indicative of a malicious document, potentially leveraging embedded JavaScript for redirection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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://synerhu.ru/uplcv?utm_term=emerald+rom+for+android PDF link annotation
    • http://goref.ru/files/file/98126009486.pdfIn PDF document text
    • http://teamhead.net/userfiles/file/81250951541.pdfIn PDF document text
    • https://wcfkenzi.com/ckfinder/userfiles/files/15043574739.pdfIn PDF document text
    • http://morecoredesign.com/images/imageUps/files/subewofovejewolefekuga.pdfIn PDF document text
    • http://hzjksj.com/images/upload/File/ruwodidutujogezafi.pdfIn PDF document text
    • http://xinchenfast.com/upload/file/39106323681.pdfIn PDF document text
    • http://gatewayhotelbangkok.com/upfile_hotel/files/pawolo.pdfIn PDF document text
    • http://fourfoods.com/images/files/99801215313.pdfIn PDF document text
    • http://oikoscoccatoarchitettura.com/userfiles/files/34796414395.pdfIn PDF document text
    • http://zussobrance.sk/grafika/dokumenty/tumugoxijuler.pdfIn PDF document text
    • http://marketypik.pl/zdjecia/fck/file/64673160505.pdfIn PDF document text
    • https://inchiriereelicopterromania.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1612f2f4dcd6d7---podepatuvidowagosumizeda.pdfIn PDF document text
    • http://mfplus.ba/wp-content/plugins/formcraft/file-upload/server/content/files/1614836cbc8009---64433978996.pdfIn PDF document text
    • http://thefutureofgolf.eu/wp-content/plugins/formcraft/file-upload/server/content/files/1612fbde204c7f---86058490396.pdfIn PDF document text
    • http://vntattoosupply.net/uploads/image/files/jawegonarasilufisabikevu.pdfIn PDF document text
    • http://connectcontrol.net/files/userfiles/files/19416750678.pdfIn PDF document text
    • https://www.vigo.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1613fb8942a5fb---26073424476.pdfIn PDF document text
    • http://autodilykanka.cz/cmsimple/images/file/tupitugijen.pdfIn PDF document text
    • http://schoonhovensvrouwenkoor.nl/ckfinder/userfiles/files/wepof.pdfIn PDF document text
    • http://remaining-mc.de/userfiles/file/sazajeramaxewog.pdfIn PDF document text
    • https://hizlipin.com/calisma2/files/uploads/golopulezej.pdfIn PDF document text
    • http://ahlhy.com/uploads/file/061753492101.pdfIn PDF document text
    • http://88cpap.com/userfiles/files/luvemobiboxisinesuma.pdfIn PDF document text
    • http://sage-chem.com/image/files/20210913_221911.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_off0000d389.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD389 10232 bytes
SHA-256: 442cd8ee9cd72b8559447dbb8c03dc683e3e71fd84d333ac28bee8801f7cd819
font_01_sfnt_off0000ea57.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA57 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010269.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10269 18388 bytes
SHA-256: cbccbe4485d78149ea75b13631f3bd92b7462298829d265a59ee3df9fd256081

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