Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef4663de92527505…

MALICIOUS

PDF

70.3 KB Created: 2021-09-18 11:28:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-20
MD5: 79577101620e78d2b7f3c2aad949943e SHA-1: bde907c926e04d7a75d8dbd37d7a57282a4788e1 SHA-256: ef4663de92527505f32450db6966fecc9bbccf518791be5424e87426cee1a00f
96 Risk Score

Malware Insights

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

The PDF contains numerous links to external websites, many of which are hosted on compromised CMS platforms or disposable domains, indicating a link farm or SEO spamming attempt. The ML classifier also flagged this PDF as malicious with high confidence. While no scripts were extracted, the structure and URL patterns suggest the document is designed to redirect users to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://pro-customer.de/userfiles/file/mozibilazeboropave.pdf In PDF document text
    • https://libyamonitor.com/sites/all/libraries/ckfinder/userfiles/files/7634302955.pdfIn PDF document text
    • http://ptk-astana.kz/wp-content/plugins/super-forms/uploads/php/files/e1de6746a930a66ceffe25960518a482/dujifi.pdfIn PDF document text
    • http://attlas.center/userfiles/file/foderokum.pdfIn PDF document text
    • https://sandipkumardutta.com/ckfinder/userfiles/files/87487868862.pdfIn PDF document text
    • https://masterok-kovka.ru/wp-content/plugins/super-forms/uploads/php/files/78a3f0ed23d19012ba1f4241dd6b00bc/posonu.pdfIn PDF document text
    • http://vizit-k.net/uploads/editor/files/13723051147.pdfIn PDF document text
    • https://ceramicasvillaflor.cl/UserFiles/File/pugarolerumulevesosa.pdfIn PDF document text
    • http://www.pranabkumar.com/fckimages/file/tagoji.pdfIn PDF document text
    • http://birkhoffhi.com/userfiles/files/36625475618.pdfIn PDF document text
    • http://cetinelektrik.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/16139461a96601---zokexosexatuziri.pdfIn PDF document text
    • https://ltes.tw-goods.com/UserFiles/files/pigiwexabaj.pdfIn PDF document text
    • http://leebyenghun.com/new/upload/board/files/zomodenidivemo.pdfIn PDF document text
    • https://conexusinternational.com/ckfinder/userfiles/file/dibekoxujitewinifa.pdfIn PDF document text
    • https://nakipoglugroup.com/upload/ckfinder/files/kanonejagas.pdfIn PDF document text
    • http://churchtextile.com/userfiles/file/welafixekikenelapirapix.pdfIn PDF document text
    • http://iktoktatas.hu/files/file/71535642386.pdfIn PDF document text
    • http://huseyindurmuslar.com/images_upload/files/belewilomo.pdfIn PDF document text
    • http://rfinshaat.az/userfiles/file/vozanaxudoxek.pdfIn PDF document text
    • http://arebiatours.com/uploads/files/pibepemalosilujefekalol.pdfIn PDF document text
    • https://www.eecpowerindia.com/codelibrary/ckeditor/ckfinder/userfiles/files/27453622863.pdfIn PDF document text
    • http://kondicionery-fryazino.ru/upload_picture/file/93896474030.pdfIn PDF document text
    • http://clerus.hu/files/file/72179001877.pdfIn PDF document text
    • http://kayapalinakliyat.com/file/zivisufaxabur.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=can+i+view+a+private+instagram+pagePDF 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_off0000b531.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB531 10612 bytes
SHA-256: f823c247ce2987fc18c218af29c3bf518f62adc43db1e211ef67a2912ef5f438
font_01_sfnt_off0000cd8b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD8B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e59d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE59D 14896 bytes
SHA-256: 6e4f8543083e15ba452d1451328110cbd181741659c5178120e07060cb56741a