Malicious PDF — malware analysis report

Static analysis result for SHA-256 1cb0cef4561b1128…

MALICIOUS

PDF

68.8 KB Created: 2021-06-06 04:13:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-07
MD5: e09f809b66cccd690529eaeb058f205d SHA-1: 4cb77529f3a2f4fb8b694ec85a9d3642a41886a7 SHA-256: 1cb0cef4561b11285ae8b77ec2fefc6acc3f491bb45d8d00b79091f57331ee44
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript T1203 Exploitation for Client Execution

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external URLs, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' confirms this, indicating the document's primary purpose is to host a large number of links for SEO manipulation or phishing. No scripts were extracted, but the presence of external links and the nature of the heuristics strongly suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://queure.ru/uplcv?utm_term=analisis+de+nodos+ejercicios+resueltos+pdf PDF link annotation
    • https://staffxrecruitment.com/wp-content/plugins/super-forms/uploads/php/files/b3f314581b7b25e45e3b3319901dd701/86502365916.pdfIn PDF document text
    • http://buergerforum-tirol.at/file/benozajoxima.pdfIn PDF document text
    • https://impariant-club.ru/wp-content/plugins/super-forms/uploads/php/files/d3bfeabc33eb5ce86ba3a4f4206e8968/padodozizetamij.pdfIn PDF document text
    • https://www.azulejositurry.com/wp-content/plugins/super-forms/uploads/php/files/k3o63g3m3cl6lsobhcam0ccbf7/13528293970.pdfIn PDF document text
    • https://www.edutechusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a5eeb46f8dd---33143964589.pdfIn PDF document text
    • http://jnnycc.org/userfiles/file/21379858987.pdfIn PDF document text
    • http://asbu.net/uploads/FCK_files/file/95275338267.pdfIn PDF document text
    • https://janeunchained.com/wp-content/plugins/super-forms/uploads/php/files/96d66ui58bv7d1i98pt95qole6/giluxakibizojaxiroxadum.pdfIn PDF document text
    • https://pablohernandes.com/wp-content/plugins/super-forms/uploads/php/files/286c0a629239ccda9e3f825ac2eac245/49805442643.pdfIn PDF document text
    • http://tanriovermensucat.com/uploads/genel/files/puvunajibalariw.pdfIn PDF document text
    • https://g-ortho.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160824817c185b---6017047983.pdfIn PDF document text
    • https://salubrismd.com/wp-content/plugins/super-forms/uploads/php/files/3486ff9cd0beff3b6e3cf7ce8da5e5f2/46548088736.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000cdb7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCDB7 5212 bytes
SHA-256: fb5ce5557df2833b5e60cdc825c8e5faf9199d57ddd250260979471e6980e096
font_01_sfnt_off0000df88.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF88 11344 bytes
SHA-256: f61576a2e86fff64bd35434741347c0a1bcc32db6006c7d9e9f86a61a99058ae

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