Malicious PDF — malware analysis report

Static analysis result for SHA-256 4da833164e3d49c6…

MALICIOUS

PDF

89.5 KB Created: 2021-07-13 17:59:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: b772979b4e24d32b12f4ab93ef029b8d SHA-1: 87687dcf53ba09786116ee82906b45ebaa029868 SHA-256: 4da833164e3d49c62b51e42fb43a7b6b13cc41a5b2b43f162ac0d6b477bb6ab9
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous links, many pointing to websites hosted on compromised CMS platforms or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://clubslotalmatriche.com/calcas/file/vubukozenuwovagusox.pdf In PDF document text
    • http://hilltoplancers1975.com/clients/13753/File/59073715794.pdfIn PDF document text
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/16076ecda281ac---67593803410.pdfIn PDF document text
    • https://reparationmobile.net/userfiles/file/84665739362.pdfIn PDF document text
    • http://www.carolglassman.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606c8e8813ad3---40437733846.pdfIn PDF document text
    • https://www.lightingdynamics.com/wp-content/plugins/super-forms/uploads/php/files/366f2704e367b7f99ac840c9a7df7504/90579125585.pdfIn PDF document text
    • https://wecafephuket.com/wp-content/plugins/super-forms/uploads/php/files/h5ab5otg2g077fn8p7ujbq1d49/65866139344.pdfIn PDF document text
    • http://stroynerud-sm.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160e6a045275ee---jabawupebodarulurovu.pdfIn PDF document text
    • https://relaxationplusmn.com/wp-content/plugins/super-forms/uploads/php/files/dd17c5c0889c7124566443905c3633bf/fofifebebidilevase.pdfIn PDF document text
    • http://kompletucetnictvi.cz/files/file/rasegavifetemogemexipan.pdfIn PDF document text
    • https://leesman.com/wp-content/plugins/super-forms/uploads/php/files/7ec29089ac4c26ea483c84f81af657c8/5420183507.pdfIn PDF document text
    • http://mfcwestenkwartier.nl/beta/userfiles/file/puxogapolenowipajezivaw.pdfIn PDF document text
    • https://www.lindopoint.it/wp-content/plugins/super-forms/uploads/php/files/b328efa18ffb8152fe1a64a374203b9d/97850515753.pdfIn PDF document text
    • http://a-range.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160af319eb2450---zutixilasa.pdfIn PDF document text
    • http://beerskiboot.com/img/upload/file/84658226540.pdfIn PDF document text
    • https://plumcourse.com/wp-content/plugins/super-forms/uploads/php/files/f026e1de5c95e2672731ba22fde0a296/vikakofo.pdfIn PDF document text
    • https://premiumvipbusiness.com/wp-content/plugins/super-forms/uploads/php/files/85b80d2020524679f9c7ca05c765759a/numemibobomamuvifa.pdfIn PDF document text
    • http://mobydick-band.de/fckdata/file/57703994732.pdfIn PDF document text
    • https://www.lumisolar.pe/wp-content/plugins/formcraft/file-upload/server/content/files/160c0bbb74eb48---15335727316.pdfIn PDF document text
    • http://raisemoneyonline.org/clients/6/69/691275cf9a36cab982b2498ebdc715be/File/58373753862.pdfIn PDF document text
    • https://xn--nmqu14inmf.com/upload/files/25831176174.pdfIn PDF document text
    • https://rescue.bg/wp-content/plugins/formcraft/file-upload/server/content/files/160ace2c0a1797---23321116879.pdfIn PDF document text
    • https://tocgia247.com/wp-content/plugins/super-forms/uploads/php/files/1j09g1c0e90vto7rap4trii0lh/riwamekavobematakoriwusel.pdfIn PDF document text
    • https://przyklejki.pl/userfiles/7384743580.pdfIn PDF document text
    • https://nobleanimalsanctuary.org/wp-content/plugins/super-forms/uploads/php/files/tmp/89871889635.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/PmAiG5ZyT-k/uplcv?utm_term=image+to+pdf+converter+free+download+for+windows+10PDF 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_off0000f91b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF91B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00011132.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11132 11240 bytes
SHA-256: bda35a71b9e8cd6b0d41996bd353f4f2a514adba7a09455146fc0458dcc10dce
font_02_sfnt_off00012b62.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12B62 17268 bytes
SHA-256: 9a7c13e475847b86b002ac7439f6194b12af604baacf014bcac40b88a04880b9

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