Malicious PDF — malware analysis report

Static analysis result for SHA-256 b51e3d41bfb806e3…

MALICIOUS

PDF

88.8 KB Created: 2021-07-04 07:34:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: d56b5d3d96856e57a7f8bf70c2a8f10d SHA-1: 5f6f0a401becb3fa9c3c17410692991af881208c SHA-256: b51e3d41bfb806e3744e498524f48ed2f8adee23eca4796675481c8a4bdc6743
136 Risk Score

Malware Insights

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

The PDF contains numerous links to external websites, many of which are hosted on compromised CMS platforms. The ML classifier and high-severity heuristics indicate malicious intent, likely to redirect users to malicious content or exploit kits. The presence of algorithmically generated URLs and link farms on disposable hosting further supports a malicious campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9952

Heuristics 6

  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://plumcourse.com/wp-content/plugins/super-forms/uploads/php/files/6fd5498c626fef92b193e23695301a57/58682760814.pdf In PDF document text
    • https://www.straightmyteeth.eu/wp-content/plugins/super-forms/uploads/php/files/7008b45d93b1fb03df0775dd3341d920/vewawipemaxikokimeruduju.pdfIn PDF document text
    • http://goldmustang.ru/files/files/48394358908.pdfIn PDF document text
    • https://amblamy.ee/upload/file/xarutiworowu.pdfIn PDF document text
    • http://www.asejnrtigers.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1607784e9e4b7d---jijolebalakekenuzedonu.pdfIn PDF document text
    • https://thejasmineway.net/wp-content/plugins/super-forms/uploads/php/files/k3fai2tk36bqjkjqcmuhrfbmq0/merosixifivugapese.pdfIn PDF document text
    • https://www.pietri-automobiles.com/wp-content/plugins/super-forms/uploads/php/files/n8ph91uqfiu93ensqprvbmasis/wevojadumukezoxowapolu.pdfIn PDF document text
    • http://kirks-pool.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608d6ae6b40ed---napodapinugefidobologesik.pdfIn PDF document text
    • https://www.reparaciondebomba.com.ar/wp-content/plugins/super-forms/uploads/php/files/7iu5tfo5qb4mlgr7dvgk8g2so1/30634701497.pdfIn PDF document text
    • http://mirembeestate.co.ug/wp-content/plugins/formcraft/file-upload/server/content/files/160ab572903658---64116566019.pdfIn PDF document text
    • https://xn----8sbaavnccwq4am.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/960685ce51e9858de693e9beb9b6ed59/46352822965.pdfIn PDF document text
    • http://epmresearch.org/userfiles/files/14214269417.pdfIn PDF document text
    • https://suhrsmad.dk/wp-content/plugins/formcraft/file-upload/server/content/files/16078e947f147c---wefosupodijefe.pdfIn PDF document text
    • https://rosemonttherapy.health/wp-content/plugins/super-forms/uploads/php/files/nkrbcc58qra8rut186a38kkt7a/jivatuvojosireb.pdfIn PDF document text
    • https://www.chortho.co.uk/wp-content/plugins/super-forms/uploads/php/files/md0kksur629b7no52f7158de8l/raxikobajonumumeroz.pdfIn PDF document text
    • http://lucidarepavimentimarmogenovaealessandria.it/userfiles/files/42641530079.pdfIn PDF document text
    • https://motionslam.com/wp-content/plugins/super-forms/uploads/php/files/6cfe86ae5ab29319d51fd6e1bbf7a85b/napas.pdfIn PDF document text
    • https://www.aironface.com/wp-content/plugins/super-forms/uploads/php/files/411f40b4f411bffdc72f1c2d5a8dba36/40037877188.pdfIn PDF document text
    • https://sip7.pl/autoinstalator/sip7.online/wp-content/plugins/super-forms/uploads/php/files/033331de2e96ac1f1021cf9c8c197c9a/15146918412.pdfIn PDF document text
    • http://pericosrentcar.com.mx/wp-content/plugins/formcraft/file-upload/server/content/files/160a0351059ada---degeromejud.pdfIn PDF document text
    • https://west-holding.com/userfiles/file/vowezitego.pdfIn PDF document text
    • https://sumangold.net.vn/wp-content/plugins/super-forms/uploads/php/files/rg7r48tf64c777f4fh8i8l52uo/55290950037.pdfIn PDF document text
    • http://hotelhoanggiaminhchauquanlan.com/img-kskc/files/kowawafegofonepug.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=welcome+students+in+online+classesPDF 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_off0000f9c5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9C5 16976 bytes
SHA-256: 0be9bb8dc8a7f00148ec056223bafc7b1f48a3165e67cae49b1ac47a52e473dd
font_01_sfnt_off000125be.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x125BE 10524 bytes
SHA-256: b6e27f42d164db68459b2021f72c16f219e2ef8ad4e2027099e38ada804d05b5
font_02_sfnt_off00013db8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13DB8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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