Malicious PDF — malware analysis report

Static analysis result for SHA-256 dc4df89b41862f3f…

MALICIOUS

PDF

73.9 KB Created: 2021-09-29 13:28:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 5b5e07e6bb0ff3d47f9dda52faf5a7c6 SHA-1: 212d58257bc6d81bd8b9de0035a4e1bdcc80d96f SHA-256: dc4df89b41862f3fe160fa36bb621dbb5fb0c6712347d358e20aa24e62df286a
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs pointing to disposable domains, indicating a link farm designed to redirect users to potentially malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://pistant.ru/uplcv?utm_term=super+mario+sunshine+64+rom PDF link annotation
    • http://sluchatka-shop.cz/files/upload/files/85917942293.pdfIn PDF document text
    • http://malir-naterac.info/UserFiles/File/58109385839.pdfIn PDF document text
    • http://abwferrellpkwy.com/uploads/files/giregamixopunazokatitimok.pdfIn PDF document text
    • https://wwa.bdbabymart.com/app/webroot/ckfinder/userfiles/files/nobujoditovijimijovunibul.pdfIn PDF document text
    • http://dulichtantai.com/files/uploaded/files/44672135124.pdfIn PDF document text
    • http://gennarimaq.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161465aa55f59b---vedojarelapu.pdfIn PDF document text
    • https://www.audioclinica.pt/wp-content/plugins/super-forms/uploads/php/files/g0n54i2hatqb0ralu3gh5vjh69/vijabixipajuxezo.pdfIn PDF document text
    • http://dobermanncz.eu/files/xirigamevuberixojabupef.pdfIn PDF document text
    • http://ladyvenus.it/userfiles/files/48184372751.pdfIn PDF document text
    • https://codecs.ro/images/file/zotuk.pdfIn PDF document text
    • http://keitbg.com/images/files/26565066978.pdfIn PDF document text
    • http://eggtesting.com/admin/uploads/file/livokawerezusijiku.pdfIn PDF document text
    • https://burkina-businessschool.com/business_school/uploads/file/82038967107.pdfIn PDF document text
    • http://hosungtour.net/FileData/ckfinder/files/20210901_BC91C797BB026DA0.pdfIn PDF document text
    • http://makrostal.pl/user_images/file/mesap.pdfIn PDF document text
    • http://kachelofen-prommegger.at/nalewemonobetikebal.pdfIn PDF document text
    • http://skpizzasubs.com/uploads/files/voxemojozedez.pdfIn PDF document text
    • https://axlthailand.com/imagexx/files/18506604361.pdfIn PDF document text
    • https://chokysitohang.com/Uploads/userfiles/files/modubuk.pdfIn PDF document text
    • http://hoachathoanggia.com/userfiles/file/34881740365.pdfIn PDF document text
    • https://didacostruzioni.it/userfiles/file/tafininos.pdfIn PDF document text
    • http://tecs4.com/intranet/ckfinder/userfiles/files/79986537119.pdfIn PDF document text
    • http://ambulatorioveterinariocamali.com/userfiles/files/23160008723.pdfIn PDF document text
    • 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_off0000b978.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB978 18608 bytes
SHA-256: 92950dcf93bd5b981a54586b6be5c2078f22435937c445759192a76ffe094424
font_01_sfnt_off0000e9b2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE9B2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000101c9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x101C9 10796 bytes
SHA-256: 449b6af1d65f74c9513b4f9aad4a8ba105116f3fce8921902e80f73f71690440