Malicious PDF — malware analysis report

Static analysis result for SHA-256 23c216d31be7ef2e…

MALICIOUS

PDF

76.1 KB Created: 2021-09-04 10:35:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 0b8cd858a77795918916f33273c02574 SHA-1: b9d0d63bfc39b4d5d56b6fd0e069a0945ad64b93 SHA-256: 23c216d31be7ef2e60fdc3c3c7fa9a93c00cd8736d7dbc075fe54fbb4b06a21d
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ClamAV and an ML classifier, with heuristics indicating it functions as a link farm pointing to compromised CMS upload storage. The document body is unreadable, but the presence of numerous URLs, many hosted on disposable domains or compromised WordPress sites, strongly suggests a phishing or malware distribution attempt. The primary attack pattern involves directing users to external malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9908

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 https://www.nosolodespedidas.es/wp-content/plugins/formcraft/file-upload/server/content/files/16089da7b66bfb---pimawawidi.pdf In PDF document text
    • http://augsburger-dartliga.de/uploads/file/nemuxedifewuvi.pdfIn PDF document text
    • https://wholisticvibrations.com/wp-content/plugins/super-forms/uploads/php/files/ad51fd7946adc02207912d961de9df0c/wexafujazubejopewi.pdfIn PDF document text
    • http://lg-palette.com/upload/files/94080545612.pdfIn PDF document text
    • http://timebank.ru/sites/default/files/photos/pagefile/15692322573.pdfIn PDF document text
    • http://pck.malopolska.pl/wp-content/plugins/super-forms/uploads/php/files/4634df398573679c592fd0966fd4362d/fonadur.pdfIn PDF document text
    • https://laplacedesstores.com/upload/file/detetipetozebutefedaraju.pdfIn PDF document text
    • http://perilatomsk.ru/ckfinder/userfiles/files/36224561427.pdfIn PDF document text
    • https://primeodontorj.com/wp-content/plugins/super-forms/uploads/php/files/1c8920636b67f87ad82d6f856fca538a/lujenorefozoderubozoxoje.pdfIn PDF document text
    • http://designbeginnings.com/upload/file/nulotudazexolurolopov.pdfIn PDF document text
    • http://chretkinia.pl/userfiles/file/52927510621.pdfIn PDF document text
    • https://www.prshots.com/ckfinder/userfiles/files/19350520042.pdfIn PDF document text
    • http://www.fullertherapy.com/wp-content/plugins/formcraft/file-upload/server/content/files/16088077aa53a9---96228150430.pdfIn PDF document text
    • https://krone-murten.ch/userfiles/files/jadenedamijulubepu.pdfIn PDF document text
    • https://weyergans-hcc.lv/userfiles/file/wakarawusipizexogekuv.pdfIn PDF document text
    • http://moskvaznaet.ru/upload/files/relawamed.pdfIn PDF document text
    • http://asalsold.com/wp-content/plugins/formcraft/file-upload/server/content/files/16071c12ea50c4---wenukoseza.pdfIn PDF document text
    • https://www.geosuiteonline.de/wp-content/plugins/formcraft/file-upload/server/content/files/160f7e7e9d4adc---50725281364.pdfIn PDF document text
    • https://www.helpagesl.org/wp-content/plugins/formcraft/file-upload/server/content/files/1608a0dce1e3f9---81619342191.pdfIn PDF document text
    • https://mymovingestimate.com/wp-content/plugins/super-forms/uploads/php/files/9428642aa3142c540744975949f71809/gopobesevurapiro.pdfIn PDF document text
    • https://cedarcreeksauce.com/wp-content/plugins/super-forms/uploads/php/files/a0b875d74e1608e329b685fe4e90445b/5739328667.pdfIn PDF document text
    • https://eclipsetheaters.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608058a4226cd---mewudawabe.pdfIn PDF document text
    • http://apluskleaning.com/admin/images/file/22207925468.pdfIn PDF document text
    • http://panel2conso.com/userfiles/file/lilusepesafopej.pdfIn PDF document text
    • http://kccmaul.com/files/files/tawunir.pdfIn PDF document text
    • http://amoy-art.com/Upload/file/kejobuwex.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=crop+pdf+windows+freePDF 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_off0000c83d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC83D 16488 bytes
SHA-256: c1632f0c362529c4dc5f0b7321cd06bda883aa4d83267400e4a57704d963ccd0
font_01_sfnt_off0000f301.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF301 10300 bytes
SHA-256: 7d06430ecb55c2d43b43f20f253981ffd790cd83a550f5bd3a6010ac44c61c49
font_02_sfnt_off00010a62.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A62 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1