Malicious PDF — malware analysis report

Static analysis result for SHA-256 5b3aca122ff4d511…

MALICIOUS

PDF

74.5 KB Created: 2021-09-04 20:10:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: e79b7b273f49cdcc9e9aea4cc3e671b6 SHA-1: 9897950f0cb46a66668cc8c313e3342baf3348e0 SHA-256: 5b3aca122ff4d511d2689ed008663f0b939d3f9216fdaae7cbdf0dab44c041d7
156 Risk Score

Malware Insights

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

The ML classifier and ClamAV detection strongly indicate malicious intent. The PDF contains numerous external links, with several pointing to compromised CMS uploads and disposable hosting, suggesting a link farm used for phishing or redirecting to malicious content. The `wkhtmltopdf` authoring application is noted, but no specific script or exploit details were extracted to further refine the family or specific attack vector beyond general phishing and exploitation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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 http://nickels.design/ckfinder/userfiles/files/11659953999.pdf In PDF document text
    • https://musikkursus.dk/userfiles/file/banose.pdfIn PDF document text
    • https://all-stage-meditation.tw/uploads/files/60c0b2aa44275.pdfIn PDF document text
    • http://komputerzagrosze.pl/userfiles/file/letexusuxelejum.pdfIn PDF document text
    • http://zlhk.ru/upload_picture/file/35065160923.pdfIn PDF document text
    • https://rugerwafers.com/demo/ruger/beta/userfiles/files/352078074.pdfIn PDF document text
    • https://aimhc.com/userfiles/file/32569254030.pdfIn PDF document text
    • http://hzkontejnery.cz/ckfinder/userfiles/files/tojovesososiriri.pdfIn PDF document text
    • https://ketgate.eu/wp-content/plugins/super-forms/uploads/php/files/593cf734c999bb0e731912784b8b5bf4/34359821499.pdfIn PDF document text
    • http://newtrichur.com/userfiles/file/14089650809.pdfIn PDF document text
    • https://www.die-umzugsfabrik.com/wp-content/plugins/formcraft/file-upload/server/content/files/160dab9b07fe8b---17251001218.pdfIn PDF document text
    • https://laetitiabernard.fr/images/file/rosagesuwolefumo.pdfIn PDF document text
    • http://3e-machinery.ru/app/webroot/filesfiles/gubotanexojoxomunusabi.pdfIn PDF document text
    • http://gerd-pollak.de/userfiles/file/92399219957.pdfIn PDF document text
    • http://rwdwebwebdesign.com/img-aim/files/18413869715.pdfIn PDF document text
    • https://sahyadrisevasanstha.in/userfiles/file/kajilujixetufagugaxexuge.pdfIn PDF document text
    • https://auditorescr.com/ckfinder/userfiles/files/53042978156.pdfIn PDF document text
    • http://jjinline.org/file_upload/file/49289103877.pdfIn PDF document text
    • https://ecef-groupe.com/wp-content/plugins/super-forms/uploads/php/files/pu3c1j30thv37bkct62osatar4/48699555203.pdfIn PDF document text
    • https://wsbe17hongkong.hk/_bin/ckfinder/userfiles/files/dibotidid.pdfIn PDF document text
    • http://goodfortune.hk/UpLoadFile/file///boginezurup.pdfIn PDF document text
    • http://9meclinic.com/ckfinder/userfiles/files/mokuruworaniteloro.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/PmAiG5ZyT-k/uplcv?utm_term=use+and+non+use+values+of+environment+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_off0000c12a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC12A 10832 bytes
SHA-256: 0d96218d6cdd61a408709c587a5ed18851cc218b1a4f9ddcf4cc7f9d465f8f96
font_01_sfnt_off0000da24.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA24 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f236.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF236 16384 bytes
SHA-256: f6c451248e1c65ad993dcc6fba5f83693cf988d6bf34a0e2f21bc87a4d19456f