Malicious PDF — malware analysis report

Static analysis result for SHA-256 5a391835a5fdfb57…

MALICIOUS

PDF

90.4 KB Created: 2021-08-13 11:34:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 8905e038b8bb0ddcfe330d1dce689b17 SHA-1: a9d5df23bce39ff55492be4c537b633a8038610a SHA-256: 5a391835a5fdfb57d6a9e5c03d30d4c87e5e8a67a07095ddf1420e56781384b7
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing or trojan. Heuristics indicate it functions as a link farm, with numerous embedded URLs pointing to compromised CMS uploads and disposable hosting domains. The document body is heavily obfuscated, suggesting an attempt to hide its malicious intent, which is likely to lure users to malicious sites for further compromise.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9822

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://windsbs.biz/files/file/votosepajivojaxa.pdf In PDF document text
    • https://www.plsok.com/wp-content/plugins/super-forms/uploads/php/files/3f20c78aeeaef9974b2cf5b3cdbf940d/ruvegugalofotukugup.pdfIn PDF document text
    • http://raczcsalad.hu/files/jamep.pdfIn PDF document text
    • http://geodeslaboratori.eu/userfiles/files/50498823240.pdfIn PDF document text
    • http://xn----gtbercbfedtm3b.xn--p1ai/admin/ckfinder/userfiles/files/42907273498.pdfIn PDF document text
    • http://asu.com.vn/wp-content/plugins/super-forms/uploads/php/files/asf2afjp0u05s1o5v2ur0uq02v/jazobobaguzamuwewawitan.pdfIn PDF document text
    • http://www.loockuniformes.com.br/home/wp-content/plugins/formcraft/file-upload/server/content/files/16094660ac718b---wiferixodosusofozimav.pdfIn PDF document text
    • http://yonezawanet.jp/units/24250/zcycom/files/loxabijegarexaf.pdfIn PDF document text
    • https://chuyennhakienvangvn.net/upload/files/vapukakexejusunejududivom.pdfIn PDF document text
    • https://sellos-mecanicos.com/wp-content/plugins/super-forms/uploads/php/files/4d34cb5e397f2246bc69527da2aeb8c7/benojowegade.pdfIn PDF document text
    • http://www.alfapilates.pl/upload/file/2751683105.pdfIn PDF document text
    • https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078e4ae2565f.pdfIn PDF document text
    • http://kardelendalgicpompa.com/uploadfiles/file/52118587207.pdfIn PDF document text
    • https://gccpay.net/wp-content/plugins/super-forms/uploads/php/files/0fbc7facd1cc43ace36337c3acdfdf37/36893455873.pdfIn PDF document text
    • http://thicongdiennuocmiennam.com/uploads/files/xarisu.pdfIn PDF document text
    • http://xycrusher.com/d/files/98168996678.pdfIn PDF document text
    • http://southportrubbish.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f11f5a95af2---54817738852.pdfIn PDF document text
    • https://www.uniqueartzz.com/wp-content/plugins/super-forms/uploads/php/files/fgic7n3nvd0ihis2t9vljan7n6/55773831580.pdfIn PDF document text
    • https://414movement.com/wp-content/plugins/super-forms/uploads/php/files/ae69ee8fbc919c1da7519ee0fe84e116/jalesiw.pdfIn PDF document text
    • https://dezsredstvompx.ru/wp-content/plugins/super-forms/uploads/php/files/123984f00049ee7c44dbe9d9a44e6991/rotugetikisulunedil.pdfIn PDF document text
    • https://comtraining.cl/userfiles/files/39646928352.pdfIn PDF document text
    • http://fujiya-burbank.com/uploads/files/lewedarinozoge.pdfIn PDF document text
    • http://martonelektro.hu/files/file/59800269911.pdfIn PDF document text
    • https://travelselection.us/wp-content/plugins/formcraft/file-upload/server/content/files/16091c61352856---digovexozuwewozotikoxeja.pdfIn PDF document text
    • https://www.sharpeningfactory.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c16e4a38d9c---wijoletasufifazi.pdfIn PDF document text
    • http://ozgu-yapi.com/firma/files/55405769577.pdfIn PDF document text
    • https://www.advids.co/wp-content/plugins/formcraft/file-upload/server/content/files/1608682ab483bc---valojebuxo.pdfIn PDF document text
    • https://agsposure.org/wp-content/plugins/super-forms/uploads/php/files/a4f0dcde246422f8fde375a8305cb93e/38129629105.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/DOqCt-cVA4I/uplcv?utm_term=best+quotes+for+friends+imagesPDF 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_off0000fb90.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB90 18112 bytes
SHA-256: f0764c71afc88da1ca8516a4c3575c422aee3933d4d603f4df8c047612ba2a13
font_01_sfnt_off00012b53.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12B53 10948 bytes
SHA-256: 1f7a255c7a4d78c7780784fac4ec258b23e755a7baa5eb609920b795778c224a
font_02_sfnt_off0001443b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1443B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1