Malicious PDF — malware analysis report

Static analysis result for SHA-256 f831504d3eaeadb8…

MALICIOUS

PDF

97.3 KB Created: 2021-06-26 14:46:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: a132a4e023318e98bf97815b91d7a342 SHA-1: 8dd9b7f232dc54261ae7cee40e9104670a1feba2 SHA-256: f831504d3eaeadb82ec14e0dc23f00b6170ccd3f3e73cb0cb49bc54e8943e7ec
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload directories, suggesting an attempt to host malicious content. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware distribution through these links. The document body is heavily obfuscated and unreadable, providing no direct user-facing content but the structure and URL findings are sufficient for this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9957

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://gamletaarnhuset.no/wp-content/plugins/formcraft/file-upload/server/content/files/160d22359a86b6---gajuzifelimulezunesekot.pdf In PDF document text
    • https://autosaloncenter.com/uploads/file/27320882552.pdfIn PDF document text
    • https://chinese-wall.tw/upload/files/tuzoruw.pdfIn PDF document text
    • https://www.sanier.pl/wp-content/plugins/super-forms/uploads/php/files/djug165cm9cd0eghoovratom1o/wujulifugukalapaz.pdfIn PDF document text
    • http://svenstavik.com/wp-content/plugins/formcraft/file-upload/server/content/files/16082eee1b75bd---vekizupeseweluxej.pdfIn PDF document text
    • https://lightingsystemscol.com/wp-content/plugins/super-forms/uploads/php/files/def0dd77b230105910de5b870d4d8bde/15442597946.pdfIn PDF document text
    • https://purpleleafestatebuyers.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c97e39d8f6c---mewewedipitafiladoxojinak.pdfIn PDF document text
    • http://www.altrus.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160bcd295e3312---bafewunojepadisavo.pdfIn PDF document text
    • http://www.uppld.org/wp-content/plugins/formcraft/file-upload/server/content/files/1607e59009e186---45271021905.pdfIn PDF document text
    • http://plusbateria.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609e182065885---97073526074.pdfIn PDF document text
    • http://gingerwooddesign.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b165dc9fd25---dotatu.pdfIn PDF document text
    • https://myphi.biz/nbloom/fckuploads/file/10404924231.pdfIn PDF document text
    • http://bluefield1966.com/clients/26642/File/80067022607.pdfIn PDF document text
    • https://1sis.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c85cba3b2fe---rejelalo.pdfIn PDF document text
    • http://admio.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1609f9bed6355a---sebovibunebegomaw.pdfIn PDF document text
    • https://livingcircles.ch/wp-content/plugins/formcraft/file-upload/server/content/files/1606c8470b3544---kadiworarezonapimawinebe.pdfIn PDF document text
    • http://mindentudor.hu/userfiles/file/rarumada.pdfIn PDF document text
    • https://lakeshoresmilesdentistry.com/wp-content/plugins/super-forms/uploads/php/files/ta7mn5f5fhq7ln614qipkqbui3/97804049442.pdfIn PDF document text
    • https://empylean.com/wp-content/plugins/super-forms/uploads/php/files/s74kteick5usebvvnp10j8hq8f/noburazipisox.pdfIn PDF document text
    • http://agnieszkapawlik.com/userfiles/file/piziwezoteveruwonoraja.pdfIn PDF document text
    • http://asesorialuishervas.com/wp-content/plugins/formcraft/file-upload/server/content/files/16075f6f07caf0---moxilajipepujojomitat.pdfIn PDF document text
    • http://www.hypnotiseur.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b58b0b73fc7---miratoluruvamuw.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=fun+things+to+do+in+a+minecraft+survival+worldPDF 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_off000117fa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x117FA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00013011.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13011 11152 bytes
SHA-256: c57170d1f8f89f9165e47b4eb3bd7308590d59b86ff5ca4c89e7cca4349fd5fb
font_02_sfnt_off000149bd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x149BD 17576 bytes
SHA-256: f48628b30e90137e79ecc5752e548dda3c328398677bd959a89045a5ff6d9fc0

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