Malicious PDF — malware analysis report

Static analysis result for SHA-256 51baf5633bb9d94a…

MALICIOUS

PDF

71.8 KB Created: 2021-09-04 00:44:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 43c3a8602d42ef64e7cec3a681c7cead SHA-1: 468b53a3a2f6920ee80f09573bf6e22503b55e68 SHA-256: 51baf5633bb9d94a0ef627aaf57b04933ca0378efe981891e02027d87344505a
156 Risk Score

Malware Insights

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

The PDF contains numerous links, many pointing to compromised WordPress sites hosting other PDFs. Heuristics indicate a link farm on disposable hosting and compromised CMS uploads, suggesting a distribution mechanism for phishing or malware. The ML classifier and ClamAV detection strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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://puertoestereo.com/wp-content/plugins/super-forms/uploads/php/files/q7emrrk90l8su4dq07s47lh87u/52015213768.pdf In PDF document text
    • https://kodcomputers.ro/2664/uploads/70932614172.pdfIn PDF document text
    • https://greshamgilessalon.com/wp-content/plugins/super-forms/uploads/php/files/3531e99e50e9dd889f7f4d379f2ab5ea/nitusaguro.pdfIn PDF document text
    • http://adanateknikservis.web.tr/wp-content/plugins/formcraft/file-upload/server/content/files/1607943c5f4133---5901591105.pdfIn PDF document text
    • https://adepotcustom.com/UploadFiles/file/20210507134837116.pdfIn PDF document text
    • http://esrafisek.com/images_upload/files/45088457645.pdfIn PDF document text
    • http://akkoryazilim.com/userfiles/file/6893872292.pdfIn PDF document text
    • http://kubak-ubezpieczenia.pl/userfiles/file/zewotenowipuvigazisolan.pdfIn PDF document text
    • https://webshopplus.nl/app/webroot/files/userfiles/files/pidawipimikak.pdfIn PDF document text
    • http://meteosputnik.ru/userfiles/file/xijetuwope.pdfIn PDF document text
    • https://discovercefalu.com/_data/images/file/16502900206.pdfIn PDF document text
    • http://objetivovender.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608e51912730f---69850555593.pdfIn PDF document text
    • https://bikeid.net/ckfinder/userfiles/files/10379508803.pdfIn PDF document text
    • http://xn--aknmedical-yub.com/uploads/file/41973977627.pdfIn PDF document text
    • https://vannordenvastgoed.nl/userfiles/file/1946536655.pdfIn PDF document text
    • https://sweetestspaparty.com/wp-content/plugins/formcraft/file-upload/server/content/files/16119ee346e511---jubiroluka.pdfIn PDF document text
    • http://przychodnia-felinskiego.pl/uploads/editor/file/limediz.pdfIn PDF document text
    • http://bugaboo-buffalo.eu/UserFiles/File/jewixubidutavopubuner.pdfIn PDF document text
    • http://francisfamilyreunion.net/clients/870293/File/69135493046.pdfIn PDF document text
    • https://matteagianotti.ch/userfiles/files/zafobelu.pdfIn PDF document text
    • http://pierrevillers.fr/mairie_files/file/90644038484.pdfIn PDF document text
    • http://www.danvillern.com/wp-content/plugins/super-forms/uploads/php/files/bv1o5rr4iq7fpkejo528a09vt1/tabobegi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=kinetic+molecular+theory+of+matter+worksheetPDF 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_off0000b935.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB935 15300 bytes
SHA-256: 2e71802dd40786530c433fc43f03fd20ac5c337f91066a5708cfa4e87064fd00
font_01_sfnt_off0000e02c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE02C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f843.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF843 10984 bytes
SHA-256: e2f916994f33752a50627e9bb5fb3c4402837904c2f7b2051dcb01f4392a88b4