Malicious PDF — malware analysis report

Static analysis result for SHA-256 51a33e5fa2b64230…

MALICIOUS

PDF

82.5 KB Created: 2021-09-05 10:12:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: a14b0b491ff7c0a9af26fcd3065a318d SHA-1: 2d58e0f4b7ac4e6b135fecddca7c576fe06d2153 SHA-256: 51a33e5fa2b64230be1b710afe6bd666e430709edafdf3d8a942a991a9f79bbb
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple external websites, some hosted on compromised CMS uploads. The document body is heavily obfuscated and appears to be metadata from the wkhtmltopdf tool, providing no direct user-facing content to analyze for lures.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9911

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://bkbflooringusa.com/userfile/abbey/file/lukejemaxaw.pdf In PDF document text
    • https://cgeminfos.ma/upload/file/86540167870.pdfIn PDF document text
    • http://anatolianlgs.com/userfiles/file/39239525958.pdfIn PDF document text
    • http://museeducuir.org/upload/files/33949547963.pdfIn PDF document text
    • https://alkalacarservice.com/public_html/userfiles/file/fisulugugexipugilutuma.pdfIn PDF document text
    • https://erdemlerkoleji.com/resimler/files/8189563553.pdfIn PDF document text
    • https://e-ssuances.com/ckfinder/userfiles/files/nefikanakizepuxoj.pdfIn PDF document text
    • https://latework.cz/soubory/batuzotivorumowifevas.pdfIn PDF document text
    • https://vestol.bg/files/file/96642905116.pdfIn PDF document text
    • https://all-stage-meditation.tw/uploads/files/6100b1bde19c4.pdfIn PDF document text
    • https://miamiuniquelimo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609dc48375d54---67567185790.pdfIn PDF document text
    • http://www.jamesbgriffinlaw.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c2c82e002ca---29270387963.pdfIn PDF document text
    • http://www.unidacardoso.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160a22cdea4c34---16803671687.pdfIn PDF document text
    • https://teplitsyoptom.ru/wp-content/plugins/super-forms/uploads/php/files/ea7571305ef143f98ef7129cc37bafd8/87571881908.pdfIn PDF document text
    • http://bezagsecurity.cz/userfiles/82632252239.pdfIn PDF document text
    • https://healthmatters.me/userfiles/file/ladidu.pdfIn PDF document text
    • http://lawyerstitleescrow.com/clients/9/9b/9b7cfcecb5e5abb6b877b2b1d59b4eb1/File/78576496074.pdfIn PDF document text
    • http://kondicionery-fryazino.ru/upload_picture/file/bebiz.pdfIn PDF document text
    • http://www.expertnutritionadvisor.com/wp-content/plugins/formcraft/file-upload/server/content/files/16094e081228a8---57162954127.pdfIn PDF document text
    • https://latrinquette.com/upload/editor/file/36157169584.pdfIn PDF document text
    • http://www.timtransportes.com/home/wp-content/plugins/formcraft/file-upload/server/content/files/1610269f885060---nilofexugolesoxatumaz.pdfIn PDF document text
    • http://kpotplace.com/uploads/files/zumufaf.pdfIn PDF document text
    • https://fentesmakina.com/paket/upload/files/vexakepiri.pdfIn PDF document text
    • https://southernlightingsource.com/wp-content/plugins/super-forms/uploads/php/files/6b3e1cc3c1bc0d35cb59ae4700ef88f5/fugafevatoduguwawinu.pdfIn PDF document text
    • http://minhanh.com/files/benagivamexedemom.pdfIn PDF document text
    • https://weblative.com/wp-content/plugins/super-forms/uploads/php/files/m4vpo4b5g04onicdk533brv4p9/misunemufumo.pdfIn PDF document text
    • http://cosmik-kinoteatr.ru/sadm_files/45554682986.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=que+es+esquizofrenia+paranoide+pdfPDF 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_off0000dd12.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD12 10712 bytes
SHA-256: f17949093d5a82237926f6e9d4b03b17a5c9b7ceb209809d2f4ee83abf362b89
font_01_sfnt_off0000f5b3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5B3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010dc5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10DC5 18180 bytes
SHA-256: b5c1df8e2ab8d320d82ac419b89f680ad57c8e5191bd80311b6b12f42f5175a9

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