Malicious PDF — malware analysis report

Static analysis result for SHA-256 b23d4274b9d83db8…

MALICIOUS

PDF

71.5 KB Created: 2021-09-30 20:04:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: c85c661cf11625f2ccadeff72ce7432e SHA-1: 3254d298c1e4c2ef4d1b0ee913ee799553884627 SHA-256: b23d4274b9d83db8de003ff781862c808e6450cc92950d8f5930bc254cb2d24a
156 Risk Score

Malware Insights

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

The PDF contains numerous external URIs and is identified as a link farm, with several links pointing to compromised WordPress upload storage. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The document body is heavily obfuscated and unreadable, providing no direct clues to its purpose beyond what the heuristics reveal.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9950

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://medvor.ru/uplcv?utm_term=mario+combat+deluxe+unblocked
    • https://datenglagi.com/contents/files/90048899908.pdf
    • https://zhbiotech.com/CKEdit/upload/files/belebixosotaje.pdf
    • http://titusauto.hu/kepek/file/visikav.pdf
    • http://betheaskssd.com/flash/betheaskssd.com/file/58413343270.pdf
    • http://www.uvhk.com/wp-content/plugins/formcraft/file-upload/server/content/files/1615319294c7e4---73842377117.pdf
    • http://garant-fond.ru/ckeditor/ckfinder/userfiles/Images/files/368454560.pdf
    • http://drivingschool-brno.eu/files/64886473401.pdf
    • http://yongchengtech.com/uploads/files/202109121053449918.pdf
    • https://futuresbuilder.net/dayafter/uploadimages/newsimages/file/25594391901.pdf
    • https://matrixx.lu/images/76016433148.pdf
    • http://smm-mm.com/uploads/news_file/67759478160.pdf
    • https://www.la-melodie-des-saveurs.fr/ckfinder/userfiles/files/sebagozaxapif.pdf
    • https://www.chauffeur-prive-nice.fr/wp-content/plugins/formcraft/file-upload/server/content/files/161462bae56e35---zodobexinisizoma.pdf
    • https://0a3exp.com/upfiles/editor/files/35589791161.pdf
    • http://adacu.org/userfiles/file/20210911155141.pdf
    • https://divorcioconsensual.com.br/wp-content/plugins/super-forms/uploads/php/files/8e945ae2379c70cc203cf5bb3bc0b106/mixasuruwumazululo.pdf
    • http://naim.naparts.com/images/fck/file/80574326313.pdf
    • http://automsystem.com/UploadFile/file/20210924215101763.pdf
    • http://hytechcommunications.com/userfiles/file/48261471681.pdf
    • http://konferencii.org/web/uploads/assets/file/besonuzodozetefowezim.pdf
    • http://www.frank-diagn.hu/userfiles/files/nuwusakijerum.pdf
    • http://ranch.pl/files/file/vefuwonamewigakosusupun.pdf
    • http://tungalag.mn/userfiles/files/68027299848.pdf
    • http://assessmentinsight.com/ckfinder/userfiles/files/wevajawomo.pdf
    • https://www.tyrtaios.gr/ckfinder/userfiles/files/30458193006.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_off0000b098.bin
fdf619c2cf00c5e8066c8f373d0fbae6602338f62f38fbe2b643ba532e0770fa
pdf-font-stream PDF embedded font (sfnt) at offset 0xB098 17676 bytes
font_01_sfnt_off0000de3f.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xDE3F 16792 bytes
font_02_sfnt_off0000f656.bin
a36a77453c74e9e7384d0bb1bcd3d38e6e193cedeea07ccac1e13671d6a335d9
pdf-font-stream PDF embedded font (sfnt) at offset 0xF656 10792 bytes