Malicious PDF — malware analysis report

Static analysis result for SHA-256 428308d60792ffc8…

MALICIOUS

PDF

86.9 KB Created: 2021-08-08 06:35:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: aa65db1d27e9e72325fd24f0589c1006 SHA-1: 42c73111c8739a430826eb1206c3546c71fdac4b SHA-256: 428308d60792ffc869ab8956e0d0cfa283a80e91730ae7bbc74696bae02928b8
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a large number of embedded URLs, many of which point to files hosted on compromised CMS upload directories or disposable hosting. The ML classifier strongly indicates maliciousness. The primary function appears to be acting as a link farm, likely for SEO poisoning or to distribute further malicious content, rather than containing an active exploit within the PDF itself.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 5

  • 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://studiobardinisrl.com/userfiles/files/47249235086.pdf In PDF document text
    • http://anthonyvienna.com/sites/default/files/file/48675937194.pdfIn PDF document text
    • https://balajitutorial.com/admin/userfiles/file/tixetudolebumuridu.pdfIn PDF document text
    • https://rjiminfra.com/wp-content/plugins/super-forms/uploads/php/files/d97a35d34208a7a96209a508789a5bab/rolut.pdfIn PDF document text
    • http://biometria.pl/photos_fck/file/27355188606.pdfIn PDF document text
    • https://apparel.allianceflooring.net/wp-content/plugins/super-forms/uploads/php/files/f1dd292b0f7b35ee4699320658da668e/dumaxurerinoragipadoxesuf.pdfIn PDF document text
    • https://nowackleverkusen.de/wp-content/plugins/formcraft/file-upload/server/content/files/16096a7059091b---bebomexan.pdfIn PDF document text
    • http://3duct.com/wp-content/plugins/formcraft/file-upload/server/content/files/16080366cca698---tufemomigetozun.pdfIn PDF document text
    • http://springswellness.net/wp-content/plugins/formcraft/file-upload/server/content/files/1608e8b753cfd8---jajoje.pdfIn PDF document text
    • https://whitelightdesign.com/wp-content/plugins/super-forms/uploads/php/files/0b3c4e9a6b2ba9151aa97ae0b75660d1/ruvum.pdfIn PDF document text
    • http://lukasikgroup.pl/Image/files/tabadelixixurariwuraxisab.pdfIn PDF document text
    • https://churchosonline.com/wp-content/plugins/super-forms/uploads/php/files/abe15c6cf3db869a14dc6efd8b77560b/66585555203.pdfIn PDF document text
    • https://peilimineko.com/userfiles/file/95477635795.pdfIn PDF document text
    • http://newtarrytowndeli.com/uploads/files/gazuzugejaku.pdfIn PDF document text
    • http://fuzoku-kyujin.jp/ckfinder/userfiles/files/35128456350.pdfIn PDF document text
    • http://doo-san.com/userfiles/file/20210730042940.pdfIn PDF document text
    • http://www.mvdisposal.com/wp-content/plugins/formcraft/file-upload/server/content/files/160de14bd66e70---moxagelilixalidudur.pdfIn PDF document text
    • http://jeugdopdewetenschapsagenda.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1609703485ef60---sevelolodilexefom.pdfIn PDF document text
    • http://alkanboya.com/files/file///23541058398.pdfIn PDF document text
    • http://unesco-mediain.cz/fckfiles/file/notumu.pdfIn PDF document text
    • http://zgkimsteszew.pl/img/upload/files/duzeke.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=manual+calefont+splendid+10+litros+ionizadoPDF 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_off0000ec23.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC23 10940 bytes
SHA-256: 1cd6dbbee75467463fd45e84b1d0a93b45b24b0e3030b2997172220a9b92f2dc
font_01_sfnt_off000105a5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x105A5 18544 bytes
SHA-256: 09c7a8916f33ed13e80692af8acce6fa684f0d18d8eb78511794bdeaf6edf505
font_02_sfnt_off00013530.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13530 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1