Malicious PDF — malware analysis report

Static analysis result for SHA-256 826cebca41550f0e…

MALICIOUS

PDF

87.5 KB Created: 2021-10-07 16:20:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: d71089208c988d585b23fba2ccf65e76 SHA-1: 2f5162865e4bc81003e6c7ba96b280256e1a051c SHA-256: 826cebca41550f0e1686e563ace5c8643ab374748a8298afe64f9dced65d372e
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. Heuristics indicate it functions as a link farm, with many URLs pointing to potentially compromised CMS upload directories or disposable hosting. The document body is heavily obfuscated and unreadable, suggesting it is not intended for human consumption but rather to host these links.

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://loscogliodifavignana.it/userfiles/files/fapexojajujujoxunobakom.pdf In PDF document text
    • http://www.gradur.ba/wp-content/plugins/formcraft/file-upload/server/content/files/1613383b7787eb---47597285807.pdfIn PDF document text
    • https://vildmarksjagt.dk/userfiles/file/44214290648.pdfIn PDF document text
    • http://nextlab-semi.com/files/fckeditor/file/1072274877.pdfIn PDF document text
    • http://benthanhsgfarm.com/images/uploads/files/32187572289.pdfIn PDF document text
    • http://dokumsuzgec.com/userfiles/files/kebisoxazadusogavitavopi.pdfIn PDF document text
    • https://saigonservices.vn/images/uploads/files/xuwazumunelitoti.pdfIn PDF document text
    • https://ttablaksystem.hu/files/file/rurug.pdfIn PDF document text
    • http://goldnumber.info/userfiles/file/94339007556.pdfIn PDF document text
    • https://nabsangram.com/userfiles/file/20046923186.pdfIn PDF document text
    • http://maskaevlawyer.ru/userfiles/file/gusewobulivinufa.pdfIn PDF document text
    • https://www.die-umzugsfabrik.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614370391f78b---woxelunotamafumuneboboj.pdfIn PDF document text
    • https://maloneslandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614452fed5275---kobaxeliwisif.pdfIn PDF document text
    • http://surtek.biz/image/files/20150409_134022.pdfIn PDF document text
    • https://kohphanganhotelandtour.com/userfiles/file/42838123304.pdfIn PDF document text
    • http://www.gpe-el.pro/ckfinder/userfiles/files/20814197216.pdfIn PDF document text
    • http://doggystylzgrooming.com/admin/photos/file/ximifenorewomonazoxasopij.pdfIn PDF document text
    • https://gopherscopes.com/userfiles/file/bebopugusokufejogozopulo.pdfIn PDF document text
    • http://davidhammerstein.org/ckfinder/userfiles/files/96584636117.pdfIn PDF document text
    • http://goodwill.pl/userfiles/file/87682013505.pdfIn PDF document text
    • http://southportrubbish.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613cfd7f64176---99411281100.pdfIn PDF document text
    • https://www.ojchamber.com/ckfinder/userfiles/files/kuduliwerovakelerog.pdfIn PDF document text
    • http://globalsocialwlefaresummit.com/app/webroot/uploads/ckuploads/files/genibowe.pdfIn PDF document text
    • https://relleno-acidohialuronico.com/wp-content/plugins/super-forms/uploads/php/files/3e757c516f56b80ec80cccc620486511/72821343298.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=neoliberalism+and+higher+educationPDF 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_off0000e9dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE9DD 11032 bytes
SHA-256: d180ed4f5f6fce2107d62822cbe1eb43b4740e14c69b4f4d5c67281f28c8a483
font_01_sfnt_off00010319.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10319 20668 bytes
SHA-256: c951961275f32eff84f8928b182f41662c733f41828147c7da8778f8a68d014a
font_02_sfnt_off0001381d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1381D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1