Malicious PDF — malware analysis report

Static analysis result for SHA-256 a3689f806a7b2b74…

MALICIOUS

PDF

87.7 KB Created: 2021-08-14 14:12:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 4c87fb4217bfb9079bbdcb1061633ff7 SHA-1: 175e7c70dc6a339b5d6ebb39d87a8a2eb0e9731e SHA-256: a3689f806a7b2b742790728a5dcdc892af4e0df90e291cc3244f77d35783438a
164 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The heuristics reveal it functions as a link farm, pointing to multiple compromised WordPress sites and disposable hosting domains. The document body is heavily obfuscated and appears to be non-readable content, suggesting it's designed to host links rather than convey information. The presence of numerous URLs, many pointing to PDF files hosted on compromised sites, strongly suggests a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

Heuristics 7

  • 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.
  • Urgency / deadline lure low SE_URGENCY_LURE
    Document contains urgency or deadline language ('account will be terminated', 'action required within 24 hours', etc.) — useful context, but low-signal without other findings
  • 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://ecomassage.pt/wp-content/plugins/super-forms/uploads/php/files/jue6203n9n5jfqir9i3h0lr9n2/rurikik.pdf In PDF document text
    • https://ohligschlaeger-berger.de/wp-content/plugins/formcraft/file-upload/server/content/files/160e21a8c2e005---kagoleposadam.pdfIn PDF document text
    • https://medicinasolidale.org/wp-content/plugins/super-forms/uploads/php/files/458b9d7b0f956d82f5d88ce98c53b848/sarubebit.pdfIn PDF document text
    • https://roweryelectra.pl/app/webroot/uploads/file/1621197264109.pdfIn PDF document text
    • https://carpanea.it/wp-content/plugins/super-forms/uploads/php/files/0772e7037fc6390ba769f8682c9129bd/nejojuta.pdfIn PDF document text
    • https://aquariumfargo.com/wp-content/plugins/super-forms/uploads/php/files/4691a49360493bd15ab1b2349a4684d7/30426099066.pdfIn PDF document text
    • http://www.predoisiasociatii.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160b7ea1ae1674---14447946247.pdfIn PDF document text
    • http://kino-profi.com/wp-content/plugins/super-forms/uploads/php/files/a00bfc5d0356074a1dea294c87444f28/12391584528.pdfIn PDF document text
    • http://www.nbrownies.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1609915e52f9d9---48203192701.pdfIn PDF document text
    • https://realimpacto.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160a174bed274a---todewejet.pdfIn PDF document text
    • http://www.next-conseil.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16079aa4f6d0f0---lemigufidur.pdfIn PDF document text
    • http://odessahighschool1970.com/clients/7/70/70263b1be1b93b62200e198143f59f20/File/fodukomoxanagawapor.pdfIn PDF document text
    • https://cls-toronto.com/wp-content/plugins/super-forms/uploads/php/files/65aec1d617bc9b72e8c02f7fa7eea6ae/vutotuvojefurotuxidetiriv.pdfIn PDF document text
    • https://www.psalighting.com/wp-content/plugins/super-forms/uploads/php/files/bee7ea60cba5e3438ac90473ea3dcd85/jokizibegigewoweka.pdfIn PDF document text
    • https://gamletaarnhuset.no/wp-content/plugins/formcraft/file-upload/server/content/files/160b805a2e9a47---zafabekilexud.pdfIn PDF document text
    • http://anneadamslaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/82436093979.pdfIn PDF document text
    • https://topclassgreenery.nl/images/file/19776260101.pdfIn PDF document text
    • https://sitebyside.ru/wp-content/plugins/super-forms/uploads/php/files/03d0560d69f5fc596e6415a3553d4299/mizej.pdfIn PDF document text
    • http://bukharageorgia.com/sites/default/files/file/berevepajejanomag.pdfIn PDF document text
    • http://hitecds.com/userfiles/file/zotirexu.pdfIn PDF document text
    • http://iamsoldierfit.com/wp-content/plugins/formcraft/file-upload/server/content/files/160be6d91f2989---dowuzunopenefuxug.pdfIn PDF document text
    • https://aaaxxion.info/images/file/45166802152.pdfIn PDF document text
    • http://ducthanggroup.com/webroot/img/files/xitoparufofow.pdfIn PDF document text
    • http://verkoop-je-wagen.be/wp-content/plugins/formcraft/file-upload/server/content/files/160bfd0f32a528---zamupevar.pdfIn PDF document text
    • https://hizlipin.com/calisma2/files/uploads/lidavemobanutof.pdfIn PDF document text
    • http://www.miamiairportlimo.net/wp-content/plugins/formcraft/file-upload/server/content/files/1607f8b3dee8ee---10984919290.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/Om9ozkHLxGw/uplcv?utm_term=what+bacteria+are+coliformsPDF 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_off0000f0be.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0BE 18120 bytes
SHA-256: 2f93ec36ba8294e6484be03a98e2e206e1fa79c803173343575663719c8e35ff
font_01_sfnt_off0001206e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1206E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013885.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13885 10632 bytes
SHA-256: 9620a85cafe359f61b7d4c80098b85d5cee711d79501eab17140383d1e88cfe5

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