Malicious PDF — malware analysis report

Static analysis result for SHA-256 857642d3f1b1ff1a…

MALICIOUS

PDF

80.8 KB Created: 2021-08-05 17:55:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-18
MD5: 2e3056aa1dfc679d7cbf0bc911508a84 SHA-1: 35b9b8e84bcba132f9475189703762d0a2379986 SHA-256: 857642d3f1b1ff1ac5d4bd4eb71d279c1f547d605d28c083ab3d06cb95e22f5b
162 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous links pointing to potentially compromised WordPress upload directories and other disposable hosting, suggesting it functions as a link farm to distribute further malicious content. The presence of a 'download button' heuristic further supports the lure-based attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.8327

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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • External URI info PDF_URI
    PDF contains an external URL action
  • 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.gs-gleichmann.de/wp-content/plugins/formcraft/file-upload/server/content/files/1609c496a6ee6a---19898217424.pdf In PDF document text
    • http://www.1atlanticfunding.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e85b3324ee7---8261283149.pdfIn PDF document text
    • http://oticonshop.com/ckfinder/userfiles/files/58075093977.pdfIn PDF document text
    • https://vieclambaohiem24h.com/upload/files/26417855624.pdfIn PDF document text
    • http://lamdecal.com/Images_upload/files/sidezajidunik.pdfIn PDF document text
    • https://nuevocoach.co.uk/wp-content/plugins/super-forms/uploads/php/files/f5da3d68a8d89398344305da095b32f1/62043597217.pdfIn PDF document text
    • https://muguet.fr/sites/default/files/file/rutududiripujutanafur.pdfIn PDF document text
    • http://prospekt-rostov.ru/ckfinder/userfiles/files/dufebesujoxetufifaxivawur.pdfIn PDF document text
    • http://teerosy.com/ipp/images/uploads/files/toseparowa.pdfIn PDF document text
    • https://shian-jin.com/UserFiles/files/54843409081.pdfIn PDF document text
    • https://accesoriosalmayor.com/images/userfiles/file/63574321149.pdfIn PDF document text
    • http://webinside.pl/userfiles/file/puzigelojipape.pdfIn PDF document text
    • http://luberoff.com/userfiles/file/sidesiwab.pdfIn PDF document text
    • https://profix.fr/ckfinder/userfiles/files/75883040877.pdfIn PDF document text
    • https://www.bocamvigliesrooms.com/wp-content/plugins/super-forms/uploads/php/files/cc5dc7168fd907e48ca3b248c0822a3d/44120664787.pdfIn PDF document text
    • http://eastmoorclassof1970.com/clients/4/43/4343e427eb1b0a0668350338a4d6b623/File/46245269100.pdfIn PDF document text
    • http://www.verneteco.com/ckfinder/userfiles/files/77374044972.pdfIn PDF document text
    • https://daluxerealty.com/wp-content/plugins/super-forms/uploads/php/files/qk0dpc70t4og1riv7bseettfj7/bibenuvok.pdfIn PDF document text
    • https://www.nordatec.com/wp-content/plugins/super-forms/uploads/php/files/2pelkd2mdkj8eb9ncs0boggil9/40413601831.pdfIn PDF document text
    • https://vettercycles.ch/userfiles/files/11630430422.pdfIn PDF document text
    • http://michardardillier.com/ckfinder/userfiles/files/xawubavojarun.pdfIn PDF document text
    • http://colescastle.com/clients/875019/File/fakefunav.pdfIn PDF document text
    • http://mesterek.net/tmp/zefuzo.pdfIn PDF document text
    • http://penoplex24.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16099c7a9a8d8f---tozalol.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/fzgW7-mxBc0/uplcv?utm_term=map+skills+worksheets+4th+grade+pdfPDF link annotation
    • 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_off0000e37d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE37D 16044 bytes
SHA-256: 134f3389b5f56f5cd8e2d5f8e2fef140c65d99089569f6a72360c29f1ede7842
font_01_sfnt_off00010d2d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D2D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012544.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12544 10920 bytes
SHA-256: f164065a2f3db58f3039d952609447249e207f26e1d7f93bd251675cbb819e0e