Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c7f61eebb1b6506…

MALICIOUS

PDF

71.1 KB Created: 2021-09-23 19:21:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 4d75c894343411fe239d34d5887198e8 SHA-1: 7d8c49bed3c450b850ceec53e38f1bbbdd77e4ff SHA-256: 4c7f61eebb1b650608c5b8bfb84282013edcb0d8b89fb5b94d093165be5d5900
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs that point to other PDF files hosted on various domains, many of which appear to be compromised or disposable. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. While no scripts were explicitly extracted, the structure suggests a link farm designed to obscure the ultimate destination and evade initial detection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9916

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 https://smidgel.ru/uplcv?utm_term=why+is+my+phone+always+lagging
    • http://yachtales.net/admin/userfiles/files/golovok.pdf
    • http://indigobaby.eu/upload/files/nubon.pdf
    • http://www.sunarsurdurulebilir.com/wp-content/plugins/super-forms/uploads/php/files/5j04eg4muqcgnuiqsv36lfcin6/bikiposi.pdf
    • http://lienming-rubber.com/uploads/files/202109171449048530.pdf
    • http://abaj.cz/UserFiles/File/95022825850.pdf
    • http://sz-nuoyi.com/Upload/file/2021090416270827334.pdf
    • http://ourpreferred.com/userfiles/files/50245206329.pdf
    • http://onlinecommerce.bg/uploads/pages/files/80506722552.pdf
    • http://hoachathoanggia.com/userfiles/file/76444762793.pdf
    • https://regenerativetherapyforpain.com/wp-content/plugins/super-forms/uploads/php/files/2f0e5b0400fdc2c96c02639c61d5968b/kalikoga.pdf
    • https://tmtteks.com/files/92146007255.pdf
    • http://filtrydokoparek.pl/img/all/bugetepefi.pdf
    • http://hiroi-es.info/yamituki-n/uploads/files/luwodefow.pdf
    • http://congseng.com/uploadfile/files/4641106784.pdf
    • https://sierrainstruments.cn/fckeditor/editor/filemanager/connectors/php/fckeditor/upload/202109/file/84547937521.pdf
    • https://webgirls-studio.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613531f22eaf2---5725063536.pdf
    • https://bdaudit.ro/userfiles/file/tajejebulolibozesuvuvim.pdf
    • http://kiajihlava.cz/UserFiles/File/dugom.pdf
    • http://al-bandak.com/userfiles/file/xovamitotaxepiwusedatu.pdf
    • https://jdconstinc.com/ckfinder/userfiles/files/lesutegoxigosawunorawaxif.pdf
    • http://fanta-life.com/userfiles/file/4501862666.pdf
    • http://studioiulianella.it/userfiles/files/gomuloreninela.pdf
    • http://akvatoria.by/UserFiles/files/duwiligebuzomabotu.pdf
    • http://gildiamasterov.ru/userfiles/file/diropesux.pdf
    • http://in-dapt.com/wp-content/plugins/formcraft/file-upload/server/content/files/161308bcdf3323---38733396053.pdf
    • https://chorland-dining.com/webroot/editor-uploads/files/voxulavezudijiliriv.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b65c.bin
9f2b5f2d5eab43f52f031cb86bd7d2ad76b7725c490994c75ccb187bf284b931
pdf-font-stream PDF embedded font (sfnt) at offset 0xB65C 10696 bytes
font_01_sfnt_off0000cebf.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xCEBF 16792 bytes
font_02_sfnt_off0000e6d1.bin
9087e961748ee8cfbedb5ba857f0015307b50b4f6533f5bdf03f57fafd2609ed
pdf-font-stream PDF embedded font (sfnt) at offset 0xE6D1 15488 bytes