Malicious PDF — malware analysis report

Static analysis result for SHA-256 ace8fc326d83716e…

MALICIOUS

PDF

81.7 KB Created: 2021-09-09 10:49:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 750f0b9cec67947a88eaab54b82dfe2b SHA-1: 5f6005b06f5f59a8c8b1d1a5f58716f2667a5995 SHA-256: ace8fc326d83716ea3a2344500535e3da537959adcf4eb68ed2b94af8911f52c
126 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, with a high heuristic firing indicating it's a link farm on disposable hosting. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or SEO poisoning by directing users to a large number of external PDF files. No scripts were extracted, and the document body was unreadable.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://nathulaldasptti.com/ckeditor/ckfinder/userfiles/files/51325753001.pdf In PDF document text
    • http://roberlo.cz/www/files/file/12569473569.pdfIn PDF document text
    • http://www.mostenpo.jp/userfiles/files/21289198940.pdfIn PDF document text
    • http://marasintl.com/public/ckfinderuploads/files/zaxolelegaw.pdfIn PDF document text
    • https://mannoorpally.com/uploads/file/49558427035.pdfIn PDF document text
    • http://mim2010.ru/userfiles/file/87991679079.pdfIn PDF document text
    • https://cualuoihoanmy.com/uploads/userfiles/file/nunajufelivimazenujifer.pdfIn PDF document text
    • http://dejede.com/userfiles/file/80699330393.pdfIn PDF document text
    • http://fthyhs.com/resource/docContentImg/file/2021-09-01/a515c14057d54829a1c89f02823409e0.pdfIn PDF document text
    • http://atenngo.com/admin/sites/site/documents/bukanegoworenotisi.pdfIn PDF document text
    • http://grappin-annat-como.com/userfiles/grappin-annat-como.com/file/xalixazotokezimojek.pdfIn PDF document text
    • https://unique-u.biz/images/uploads/file/23514853080.pdfIn PDF document text
    • https://airflow-skateboards.com/userfiles/files/30886085621.pdfIn PDF document text
    • http://stitesattorney.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/sakuladosomarawag.pdfIn PDF document text
    • https://www.syah.org/wp-content/plugins/super-forms/uploads/php/files/7730dc2ddc4cc143994bbb2c5c01b225/88661315701.pdfIn PDF document text
    • http://cdkuys.handysociality.com/upload/files/bawilegewub.pdfIn PDF document text
    • https://uclerbaklava.com/resources/file/72175999297.pdfIn PDF document text
    • http://aire-limpio.com/img/editor/file/58964136755.pdfIn PDF document text
    • http://zentrumok.com/userfile/files/82461955787.pdfIn PDF document text
    • http://progfin.pl/userfiles/file/gijekuretalajavifurikil.pdfIn PDF document text
    • https://www.booster-p.com/wp-content/plugins/formcraft/file-upload/server/content/files/16132ccf826d60---ropab.pdfIn PDF document text
    • https://ceral.pl/ceral/pliki/file/29361686228.pdfIn PDF document text
    • http://cuacuonbinhduong.com/upload/files/23269110551.pdfIn PDF document text
    • https://xn--fiqa735be48e.com/upload/files/xeleberetelaguwe.pdfIn PDF document text
    • http://elskup.pl/images/assets/file/pudemaxo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=high+accuracy+location+androidPDF 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_off0000d969.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD969 18156 bytes
SHA-256: 08b8b740eb7ccaf03c5d94cf306a154b7e7649b6d945eb3bb73d563fb49e1843
font_01_sfnt_off0001092b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1092B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012142.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12142 10556 bytes
SHA-256: f1ecca149159b9db92ef230b6f3173ee07962412f085e299102bc9e5634c6563