Malicious PDF — malware analysis report

Static analysis result for SHA-256 8df633a79ca8b7dc…

MALICIOUS

PDF

81.0 KB Created: 2021-09-08 19:19:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: dc4ce449b49390b9d5ece5f357458d81 SHA-1: 925fbed80ca884004ac7c2d1c8b19fb2e8c42fae SHA-256: 8df633a79ca8b7dcecfccd8632b73685c370ea02b11cd907c95087fd3ecc3e32
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised CMS uploads or disposable hosting, indicating a link farm designed for malicious redirection. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but reinforcing the nature of the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://cructi.ru/uplcv?utm_term=basic+geometry+worksheets+grade+7 PDF link annotation
    • https://rajatotogroup4.com/contents/files/83800419834.pdfIn PDF document text
    • http://maurovalleferroarchitetto.eu/userfiles/files/geroximupefi.pdfIn PDF document text
    • https://tele-video.ru/upload/files/kegaxupibaritesota.pdfIn PDF document text
    • http://3e-recycling.ru/app/webroot/filesfiles/gizizage.pdfIn PDF document text
    • http://kamnitikamini.si/upload/files/lenuxaguxub.pdfIn PDF document text
    • http://tearose-kitchen.com/sites/default/files/images/imcefile/87842845417.pdfIn PDF document text
    • http://vititanon.com/user_img/files/35948067105.pdfIn PDF document text
    • http://creative-format.com/upload/editor/files/68043233155.pdfIn PDF document text
    • http://worldsocialistpartyindia.org/ckfinder/userfiles/files/27469491858.pdfIn PDF document text
    • https://curewelldiabetes.com/userfiles/file/bevazidudal.pdfIn PDF document text
    • http://likebarcode.com/image/files/20210907_111340.pdfIn PDF document text
    • https://erdenet.mn/userfiles/file/wojoxarum.pdfIn PDF document text
    • https://doitoutdoorz.com/file/7EDw1UyDdjbk5ZLO.pdfIn PDF document text
    • https://bocrangsuthammy.vn/upload/files/53601029191.pdfIn PDF document text
    • http://www.adanakursmerkezi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f5266d501c---89736321853.pdfIn PDF document text
    • http://vidol.nl/userfiles/file/59223586206.pdfIn PDF document text
    • https://vsevolozhsk.mebel18.com/uploads/files/marepav.pdfIn PDF document text
    • https://arizonapoolcontractor.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612fff87e2dd8---xuritanubegiz.pdfIn PDF document text
    • http://imhome-listings.com/userfiles/files/wukevor.pdfIn PDF document text
    • https://beruanglucu.com/contents/files/73490249660.pdfIn PDF document text
    • https://kamber.dk/wp-content/plugins/super-forms/uploads/php/files/2157888d9ca78e20bdaf129f756640bd/xolalutinunitofumo.pdfIn PDF document text
    • https://jvlegacyhomerepairsmd.com/nbloom/fckuploads/file/gikevatapegofosazi.pdfIn PDF document text
    • https://fond.ru/userfiles/file/44813601724.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_off0000d79e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD79E 11060 bytes
SHA-256: e90dc010011087d2852db658a270de71cb07e438f817708e3e43ad7efc11ce3a
font_01_sfnt_off0000f162.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF162 16764 bytes
SHA-256: fc43cc1379f63d30c540083b90e69d553272532d4362879fe2f31dfc35c8d2ef
font_02_sfnt_off00011cd0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11CD0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1