Malicious PDF — malware analysis report

Static analysis result for SHA-256 c21df256178bfcaf…

MALICIOUS

PDF

79.8 KB Created: 2021-09-13 16:57:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-22
MD5: 8e53957fe68065452bcd8feac8517d30 SHA-1: 30428631cb7f54cf18a6db20f310c191270754d5 SHA-256: c21df256178bfcaf0bd2ec9d6ae7f65d58cc2c239b10e6c8bea0e20ad01bc18a
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains a link farm with numerous embedded URLs, many pointing to compromised CMS upload storage or disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware distribution. No scripts were extracted, and the document body was unreadable, but the heuristic firings and URL analysis are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

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 http://www.culturehousesun.org/photos/file/83965155242.pdf In PDF document text
    • http://remont-elektro.eu/archiv/file/venulirug.pdfIn PDF document text
    • http://oldmotorsclub.com/files/file/kitetuxiridogalejadesit.pdfIn PDF document text
    • https://amd-export.com/site/upload/file/waroru.pdfIn PDF document text
    • http://noclegsosnowiec.pl/eurostyl/photos/file/80057911623.pdfIn PDF document text
    • http://carneslaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/gedalawuxuposad.pdfIn PDF document text
    • http://mqskin.com/luutru/files/49149638866.pdfIn PDF document text
    • https://veritiesinstitute.com/wp-content/plugins/super-forms/uploads/php/files/11d34c795eae7d1c850c7eaaeca84892/84793318495.pdfIn PDF document text
    • http://structurecreative.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f616e8d8f2---20632946914.pdfIn PDF document text
    • https://www.simplythebestevents.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1613de4cb67bd4---rakogopolujuzelob.pdfIn PDF document text
    • http://akpanlawoffice.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/zonibuxafuxogunivimuno.pdfIn PDF document text
    • http://shsuorui.com/uploadfiles/fckeditor/20210912/file/16314526178806.pdfIn PDF document text
    • http://canshu.dlzj.net/upload/files/202109032001235666.pdfIn PDF document text
    • https://chsins.tw/uploads/files/202109050501554063.pdfIn PDF document text
    • https://marcvandewiele.com/userfiles/file/gotubukifuxadanewogirija.pdfIn PDF document text
    • http://ace-pharm.com/upload/files/60024774513.pdfIn PDF document text
    • http://www.startservis.sk/novy/ckfinder/userfiles/files/11309496811.pdfIn PDF document text
    • https://rubyyadav.com/nbloom/fckuploads/file/69486236911.pdfIn PDF document text
    • http://chizclean.ru/files/fck/file/wobawewuponosesokesi.pdfIn PDF document text
    • http://jaqalsports.com/files/file/87582376207.pdfIn PDF document text
    • https://parquesanalbertohurtado.cl/ckfinder/userfiles/files/3251231470.pdfIn PDF document text
    • http://mdbim.pl/ubezpiecz/obrazy/file/pivewigum.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1xuhb7AK25c/uplcv?utm_term=tr+blends+word+listPDF 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_off0000d728.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD728 16808 bytes
SHA-256: d6d20e7f1dfca84fd3f66c775da1d752f85e70855ad5b7dcae88b2480f0eae96
font_01_sfnt_off000102db.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x102DB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011af2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11AF2 10268 bytes
SHA-256: 674945fa282657bb4b9d9d7bd491fe8327a18f85bb9e2f9547accbac6ca2d407