Malicious PDF — malware analysis report

Static analysis result for SHA-256 c5c51083c1aa2bdd…

MALICIOUS

PDF

77.1 KB Created: 2021-07-01 15:36:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: cbefaa11d5d2cdc58243d0c3d18fa562 SHA-1: fbff48909a0972c190fbeb14f323e0ba50aee5f1 SHA-256: c5c51083c1aa2bdd94d8d595805c67fa38b1353880b36e0438306961befa4f4d
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It functions as a link farm, with numerous embedded URLs pointing to potentially compromised CMS uploads and disposable hosting, suggesting a phishing or SEO manipulation scheme. Although no scripts were explicitly extracted, the PDF structure and embedded URIs are indicative of malicious activity, likely involving the exploitation of PDF viewers or social engineering.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9943

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://audit-advisers.com/userfiles/file/sojetujozigokedeturo.pdf In PDF document text
    • https://armandofalconi.net/userfiles/file/17103811370.pdfIn PDF document text
    • http://taskentcompany.com/userfiles/file/97190421838.pdfIn PDF document text
    • http://immobilieninvestors.eu/userfiles/file/xesajamonagojorisodo.pdfIn PDF document text
    • http://bestapp4u.com/admin/uploadedfiles/file/puxasamutukubanegaxevep.pdfIn PDF document text
    • http://gingerwooddesign.com/wp-content/plugins/formcraft/file-upload/server/content/files/160cfa32d1e625---tosileterid.pdfIn PDF document text
    • http://fantasypartyentertainment.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a47fea0f333---lamepebuwutejima.pdfIn PDF document text
    • http://www.fsnn.se/wp-content/plugins/formcraft/file-upload/server/content/files/160c798049f57c---nivozujuzafojefe.pdfIn PDF document text
    • http://dodici12.ru/wp-content/plugins/super-forms/uploads/php/files/82np8c0tr7fet7s61fpui7ujm3/24323752091.pdfIn PDF document text
    • https://lightsourceindiana.com/wp-content/plugins/super-forms/uploads/php/files/32d89f0f763c8a6eac503f8bb1919dd0/65144855322.pdfIn PDF document text
    • https://buka.ru/sadm_files/62391244139.pdfIn PDF document text
    • https://alcc.vn/wp-content/plugins/super-forms/uploads/php/files/789vqq67oo2kn3c232rnbne2p8/fesenezisapiwatixawaju.pdfIn PDF document text
    • https://btsmstlucia.com/atomicsteps/upload/userfiles/file/39832998673.pdfIn PDF document text
    • http://osullivanspressurewashing.com/wp-content/plugins/formcraft/file-upload/server/content/files/16098844aa6c82---79139685551.pdfIn PDF document text
    • http://countrysquirefoods.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a8e278ccc58---lexosamufali.pdfIn PDF document text
    • http://acmemask.com/upfiles/editor/files/22649413300.pdfIn PDF document text
    • http://adabaskimerkezi.com/upload/file/gorak.pdfIn PDF document text
    • http://amwordpress.org/wp-content/plugins/formcraft/file-upload/server/content/files/16099aa2d048e9---rumonexerelizojuj.pdfIn PDF document text
    • https://laxmigrouppune.com/wp-content/plugins/super-forms/uploads/php/files/e40b78b301e244df536a39f48620644e/83769760471.pdfIn PDF document text
    • https://engravestone.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607ec9da3bf03---87206118497.pdfIn PDF document text
    • http://www.fattyweng.com.sg/wp-content/plugins/formcraft/file-upload/server/content/files/16078c8a3ebfd5---95089683112.pdfIn PDF document text
    • https://www.energetisch-therapeut-estie.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1607d0572ee85a---72211870731.pdfIn PDF document text
    • http://www.pianoszimmermann.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16082e39b63555---zilerugezigifubavojibik.pdfIn PDF document text
    • https://nada70.org/userfiles/file/vuwaxuzararew.pdfIn PDF document text
    • https://massagetheory.ca/wp-content/plugins/super-forms/uploads/php/files/0df09bcf8515f011dbd299c95176be93/6397491156.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=inverse+function+differentiationPDF 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_off0000cd1e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD1E 10540 bytes
SHA-256: 4392263b7a3a52ecc25191d2c0af5d4897828158d9074b58197505e972f34c0e
font_01_sfnt_off0000e554.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE554 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fd66.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD66 16152 bytes
SHA-256: a01ee0af09d171870ef4a6ca087d6c3fe9ef09ef0b60b83d32d49752e3db89d2

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