Malicious PDF — malware analysis report

Static analysis result for SHA-256 818f5525fc5d01ab…

MALICIOUS

PDF

73.4 KB Created: 2021-09-20 04:51:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 71b443f2ef9d083d8bc40eed294c11ae SHA-1: fa0a4f242c51b1c4dd2302921cc172ec5378c4e0 SHA-256: 818f5525fc5d01ab3c2331bf0d71eafc32b9744a3a62fcc1b738d8a9d6b32ab3
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file contains numerous embedded URLs, many of which point to compromised websites or disposable hosting, characteristic of a link farm. The ClamAV detection and ML classifier strongly indicate malicious intent, likely phishing or SEO spam. No scripts were extracted, and the document body was unreadable, limiting the analysis to the URL structure and heuristic findings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://ivelinabozilova.com/userfiles/file/vedopilarinasevorowiko.pdf In PDF document text
    • http://talk200.com/admin/admin/uploadfiles/file/72321057636.pdfIn PDF document text
    • https://pjkconstruction.ca/images/file/vigiledid.pdfIn PDF document text
    • http://digifast.cz/userfiles/sewaxoparoj.pdfIn PDF document text
    • http://radio-salsa.fr/php/rs/filesupload/file/99612205929.pdfIn PDF document text
    • http://kemnhapkhau.com/upload/files/wulibonixupujemepezizore.pdfIn PDF document text
    • http://munnarinfo.in/userfiles/file/lunusoxawuxa.pdfIn PDF document text
    • http://paillasse.hu/userfiles/file/gibelujuzag.pdfIn PDF document text
    • https://xn--fct5g39pjpo.tw/upload/leakstop/files/62569332262.pdfIn PDF document text
    • http://pcccphucvinh.com/upload/files/titisutaj.pdfIn PDF document text
    • http://sinoorchids.com/image/file/50740763451.pdfIn PDF document text
    • https://www.hotelamoha.it/wp-content/plugins/formcraft/file-upload/server/content/files/16135974cc0564---laxedimik.pdfIn PDF document text
    • https://keluargamimpi.com/contents/files/68968870727.pdfIn PDF document text
    • http://ednak.com/wp-content/plugins/formcraft/file-upload/server/content/files/16143a67526e20---lajofavez.pdfIn PDF document text
    • http://alajwakh.com/uploaded_files/userfiles/files/toxelavanarenurabixunal.pdfIn PDF document text
    • http://greece-ex.com/images/blog/file/jarezevexevafubukew.pdfIn PDF document text
    • https://vietnaminsight.biz/ckfinder/userfiles/files/ditotulofiresojedavi.pdfIn PDF document text
    • http://4bx.pl/public/file/bawakojave.pdfIn PDF document text
    • http://1yunnan.com/ckfinder/userfiles/files/25461946551.pdfIn PDF document text
    • http://www.shipsupply.co.mz/wp-content/plugins/formcraft/file-upload/server/content/files/161435f7b1585c---49480918735.pdfIn PDF document text
    • http://sieuthibongda.net/ckfinder/userfiles/files/motudidimimutubiseg.pdfIn PDF document text
    • https://www.hippocratio.gr/ckfinder/userfiles/files/fopedotorurivanuzisorunix.pdfIn PDF document text
    • http://tuzy.pl/Upload/file/58785183685.pdfIn PDF document text
    • http://kleinschadenexperte.de/userfiles/file/jupitanu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=4x4+dirt+offroad+parking+mod+apkPDF 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_off0000bb1d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBB1D 10672 bytes
SHA-256: 40f99bf932ebef73b8f3abcaf13cfb4de5b142b59030157341abb5eccd0a4f8f
font_01_sfnt_off0000d350.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD350 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000eb62.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB62 17240 bytes
SHA-256: 723e1cb3f45a7bf55d54233dd2ae3c124f0741384648a7d5c9c0ecf623bc3600