Malicious PDF — malware analysis report

Static analysis result for SHA-256 6556e092815ca73c…

MALICIOUS

PDF

82.5 KB Created: 2021-09-12 03:48:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 9b39310c9dbbdbcf57726cfe62782086 SHA-1: 402a350f5cefe4b31955a57efe1914780e08f253 SHA-256: 6556e092815ca73c170b61beef2612aae955c4f929d314c654488e3b4e550cf7
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many pointing to compromised CMS uploads or disposable hosting, suggesting a link farm designed to lure users to malicious sites. The presence of external URI heuristics further supports this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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://st-ark.it/userfiles/files/90102139020.pdf In PDF document text
    • http://www.immiflex.com/wp-content/plugins/formcraft/file-upload/server/content/files/161324341c7e8e---71864678567.pdfIn PDF document text
    • http://longtra.vn/userfiles/file/18555572322.pdfIn PDF document text
    • https://almuhja.net/ckfinder/userfiles/files/wekodoputorodo.pdfIn PDF document text
    • https://manajrgvaaradhi.com/cms-uploads/files/45086727362.pdfIn PDF document text
    • https://ehblending.com/wp-content/plugins/super-forms/uploads/php/files/937870b2e2dcaddf9e76f610437740a4/38671465458.pdfIn PDF document text
    • http://www.sunarsurdurulebilir.com/wp-content/plugins/super-forms/uploads/php/files/omv7ou7kt4jejgqk6mlm5qh5j1/52748295623.pdfIn PDF document text
    • https://luathoanghuy.com/uploads/files/widoxowisaxe.pdfIn PDF document text
    • http://www.uvhk.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137a5eb91f0b---fuvabanifexavovilufolige.pdfIn PDF document text
    • https://insinkerator.us/images/uploaded/file/15874962345.pdfIn PDF document text
    • https://tennis-samara.ru/img/file/19993945381.pdfIn PDF document text
    • https://www.vignolaweb.it/ckfinder/userfiles/files/kaxupezate.pdfIn PDF document text
    • https://bibliotheque-des-arts.com/ckfinder/userfiles/files/76715043499.pdfIn PDF document text
    • https://jcmimoveis.com/userfiles/file/92820093800.pdfIn PDF document text
    • http://uitvaartverzorgingsindex.nl/images/uploads/4825209385.pdfIn PDF document text
    • http://na3.it/misc/file/rumewanagoredejubudowal.pdfIn PDF document text
    • http://dailynewsodia.com/assets/ckfinder/core/connector/php/uploads/files/19439077574.pdfIn PDF document text
    • https://mgs-on-track.com/app/webroot/userfiles/file/bizesunivitemaxasafipoto.pdfIn PDF document text
    • http://prospekt-rostov.ru/ckfinder/userfiles/files/nozakete.pdfIn PDF document text
    • http://sys-svinding.dk/userfiles/file/7005484250.pdfIn PDF document text
    • https://dm288.rs/slicice/file/lujokoj.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/DOqCt-cVA4I/uplcv?utm_term=how+to+set+a+live+photo+as+wallpaper+on+iphone+sePDF 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_off0000df24.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF24 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f73b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF73B 10492 bytes
SHA-256: 7e352f367da06a278a1bb3b6f77b5008d8d6b644c99e7e007488a28896eecc78
font_02_sfnt_off00010f11.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F11 17608 bytes
SHA-256: b06521ca984d223db2fa6e692f7c434ec3ab76b69eaf1ea52234440dace5764e