Malicious PDF — malware analysis report

Static analysis result for SHA-256 d91cbcdac3d11be8…

MALICIOUS

PDF

81.3 KB Created: 2021-09-19 08:58:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: da84ba7244c5c2969c377eafd907a1b3 SHA-1: f3d61b64ded97e2e07656cc1ff59098fc6f5b660 SHA-256: d91cbcdac3d11be8af30f8338d97fc2a7952aa2b8a6270534dcdd0a08499d35b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains numerous embedded URLs, many of which point to compromised websites or disposable hosting, indicative of a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely to redirect users to phishing sites or download further malware. No scripts were extracted, but the PDF structure itself is used to host and distribute these malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://smidgel.ru/uplcv?utm_term=delete+all+phone+contacts+android PDF link annotation
    • http://skolky.info/foto/images/file/28965759127.pdfIn PDF document text
    • http://bkmarine.net/ckfinder/userfiles/files/1631916096.pdfIn PDF document text
    • http://leebyunghun.org/new/upload/board/files/vopotituropumota.pdfIn PDF document text
    • http://studioingtassinari.eu/userfiles/files/rojewejiroj.pdfIn PDF document text
    • http://airmon.hu/images/files/sixevopigadivaxis.pdfIn PDF document text
    • http://umbabox.com/userfiles/file/16252261737.pdfIn PDF document text
    • http://ebslang.net/_UploadFile/Images/file/53275740409.pdfIn PDF document text
    • https://justforjetscatering.com/userfiles/image/files/95257751488.pdfIn PDF document text
    • http://darstin.com/userfiles/files/64796106757.pdfIn PDF document text
    • https://ww150003.linebot.net/upfile/files/20210913100149.pdfIn PDF document text
    • http://goksirkrupskimlyn.pl/img/upload/files/kikekupu.pdfIn PDF document text
    • https://bestmiamiturf.com/wp-content/plugins/super-forms/uploads/php/files/f2e2e57b12fa1cc8cd70e432be2fdf53/movitutonezavoxigepa.pdfIn PDF document text
    • http://ephtour.com/FileData/ckfinder/files/20210908_1C45F0BDE2989637.pdfIn PDF document text
    • http://hodori247.com/uploads/files/71224210348.pdfIn PDF document text
    • https://interstudy.net/userfiles/file/makedukasuf.pdfIn PDF document text
    • http://aaaexpressheating.com/userfiles/file/62838061244.pdfIn PDF document text
    • http://www.rannatennis.ee/data/upfiles/files/jefibifefuwixesavoj.pdfIn PDF document text
    • https://inwestorfinanse.pl/userfiles/file/suritixodo.pdfIn PDF document text
    • http://musicpark-live.de/userfiles/file/wudomufolonogojotowid.pdfIn PDF document text
    • http://trufeel.com/ckeditor/ckfinder/uploadfile/files/42604758097.pdfIn PDF document text
    • https://swapnauraan.com/ckfinder/userfiles/files/tugasax.pdfIn PDF document text
    • https://regalcabs.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1613f4e147aa18---70823882932.pdfIn PDF document text
    • http://anhuishangbiao.com/upload_fck/file/2021-9-18/20210918215612515831.pdfIn PDF document text
    • https://ehblending.com/wp-content/plugins/super-forms/uploads/php/files/b1d20910f31c0f6f4a08f2dca51e9f57/bivuni.pdfIn 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://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_off0000d611.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD611 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ee23.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE23 18988 bytes
SHA-256: 46a56107bdcea5de94fdc9d0cb517a5ef13982c02dba214633db2884e19f2005
font_02_sfnt_off00011f61.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F61 10612 bytes
SHA-256: ffcc75b607fa109fde74467a01527256c59fda7ad2f98bd10c2e6f09ecfaeb7a