Malicious PDF — malware analysis report

Static analysis result for SHA-256 8f639e7fc2f55715…

MALICIOUS

PDF

81.5 KB Created: 2021-07-27 22:55:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: c1e0cb0eb36cfd07cf20abf2e050b320 SHA-1: 35545b29690ad7cc4e0a4fa55ecf447e3d5df381 SHA-256: 8f639e7fc2f557156e0945113823d49e9fbbb03d5938e865f9c0f0c0e18b4eec
156 Risk Score

Malware Insights

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

The PDF was identified as malicious by ClamAV and an ML classifier, with heuristics indicating it functions as a link farm. Multiple external URLs pointing to other PDF files on various domains were extracted, suggesting a redirection mechanism. The document body was unreadable, but the presence of numerous links on disposable hosting points towards a phishing or SEO poisoning campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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 http://mojahotels.com/ckfinder/userfiles/files/66313278561.pdf In PDF document text
    • http://www.sealjet.mn/pictures/files/49021574330.pdfIn PDF document text
    • http://altaprecision.com/userfiles/file/77600184415.pdfIn PDF document text
    • https://bestmiamiturf.com/wp-content/plugins/super-forms/uploads/php/files/5a61c3f23eeb2ea95063da8c36f75c89/43241308413.pdfIn PDF document text
    • https://ikitellirezistans.com/upload/files/79428489297.pdfIn PDF document text
    • http://www.kickcommerce.com/userfiles/file/bugom.pdfIn PDF document text
    • http://dlmberatung.ch/userfiles/files/36903018957.pdfIn PDF document text
    • https://gamedunyasi.com/calisma2/files/uploads/49584647554.pdfIn PDF document text
    • http://comp-art.ru/userfiles/file/32169326570.pdfIn PDF document text
    • https://impariant-club.ru/wp-content/plugins/super-forms/uploads/php/files/af07dbfd3aef09cacfc449a746bce2e4/80338682140.pdfIn PDF document text
    • http://propellerclubsandiego.org/uploads/files/13250707681.pdfIn PDF document text
    • http://brukbet.com/user_images/file/dijufaje.pdfIn PDF document text
    • http://trackeg.com/en/wp-content/plugins/formcraft/file-upload/server/content/files/160cadedbc3f14---37089880336.pdfIn PDF document text
    • http://ever0036.com/assets/uploads/ckedit/files/20210628110737.pdfIn PDF document text
    • https://aljazeerahpetroleum.ae/userfiles/files/7569598501.pdfIn PDF document text
    • https://www.booster-p.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609606d92b7de---fafikejidisonimax.pdfIn PDF document text
    • https://carstenrath.com/wp-content/plugins/super-forms/uploads/php/files/l5skenlsbd5rstdcp8dmq3gi2r/14496256079.pdfIn PDF document text
    • http://qboardapp.com/wp-content/plugins/super-forms/uploads/php/files/8ed874430fb8e4ab2db33e8f8cc465d1/22636024628.pdfIn PDF document text
    • https://f1com.ge/wp-content/plugins/super-forms/uploads/php/files/6abd5a3641f825d76decfed747907151/93504689156.pdfIn PDF document text
    • http://suapaiatuipelehakefamily.com/clients/80707/File/fumilivazaz.pdfIn PDF document text
    • https://pousadamarazul.tur.br/wp-content/plugins/formcraft/file-upload/server/content/files/16080f110a0791---xefefupeveniralarekowem.pdfIn PDF document text
    • http://fairview66.org/clients/866114/File/6083544208.pdfIn PDF document text
    • http://clubselectionvoyages.net/images/file/jiserudijabane.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/LPIa9PGmDLg/uplcv?utm_term=perdida+de+carga+en+conductos+circularesPDF 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_off0000d8cb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD8CB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f0dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0DD 17660 bytes
SHA-256: 5abea9d6857809b5f12bd2239705aad3a2df3c09ddb75854e589c2ceee309a20
font_02_sfnt_off00011dd9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11DD9 10648 bytes
SHA-256: fb842c427ce76541c4be80ece7260a39b3c3042e37ea65f4b94daeeb190e14dd

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