Malicious PDF — malware analysis report

Static analysis result for SHA-256 61a4589a14ba75d5…

MALICIOUS

PDF

91.3 KB Created: 2021-10-16 12:08:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: a3efd373f0ac71ae46ba14bc695f6ea5 SHA-1: 0851f9d19f9c68070df438dcfc73f3ddb889b9ce SHA-256: 61a4589a14ba75d507584fbeaf405f3ffab7114091bedcc490ab876073b7dbc9
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs pointing to disposable domains, indicating a link farm designed to obscure the ultimate destination. The presence of PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, suggesting a phishing or spamming campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

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 https://discovercefalu.com/_data/images/file/91726746889.pdf In PDF document text
    • http://xhzhengli.com/upload/11541145482.pdfIn PDF document text
    • http://osc-pribor.ru/products_pictures/file/sunufon.pdfIn PDF document text
    • http://studioaeditecne.it/userfiles/file/dubokurewewejifonavugod.pdfIn PDF document text
    • https://filetorme.com/upload/files/96147610406.pdfIn PDF document text
    • http://www.chubsorn.com/file/files/64629696744.pdfIn PDF document text
    • http://sspvjd.com/FileData/ckfinder/files/20210908_470FEDC447732BE9.pdfIn PDF document text
    • https://ristovski.mk/public_html/upload/userfiles/file/zotumasapagatekip.pdfIn PDF document text
    • https://www.la-melodie-des-saveurs.fr/ckfinder/userfiles/files/fikegu.pdfIn PDF document text
    • http://studiosaletta.it/userfiles/files/70685179741.pdfIn PDF document text
    • https://net-mex.hu/ckfinder/userfiles/files/sedamuranavexalisumipu.pdfIn PDF document text
    • https://www.sibirprokat.ru/ckfinder/userfiles/files/6915818029.pdfIn PDF document text
    • http://knshzj.com/CKEdit/upload/files/4204192502.pdfIn PDF document text
    • https://mediaskills.rs/files/61244597889.pdfIn PDF document text
    • https://dol-rtknetwork.com/uploads/files/takunofubuxegisogide.pdfIn PDF document text
    • http://agilesolutions.in/uploads/vefefipegeji.pdfIn PDF document text
    • https://highlander-inn.com/assets/userfiles/files/30666337370.pdfIn PDF document text
    • https://provisionsinternational.com/wp-content/plugins/formcraft/file-upload/server/content/files/1615951cc25069---paduxugubelis.pdfIn PDF document text
    • https://nsck-cykelmotion.dk/userfiles/file/xubumufokorewod.pdfIn PDF document text
    • http://agro-vostok.ru/userfiles/file/jesesoduboxuwojonax.pdfIn PDF document text
    • http://hnhappiness.com/d/files/naxadegavolazefukakolute.pdfIn PDF document text
    • http://srihemkuntsahibfgp.org/hemkunt/userfiles/file/15110271566.pdfIn PDF document text
    • http://aibasylhet.edu.bd/app/webroot/ckfinder/userfiles/files/88188768481.pdfIn PDF document text
    • http://startent.ru/SITE/files/editor/file/riwanopenixurerog.pdfIn PDF document text
    • http://feedproxy.google.com/~r/Xvkpad/~3/1hHberoKktI/uplcv?utm_term=box+and+blocks+test+normsPDF 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_off0000ff99.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF99 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000117b0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x117B0 10824 bytes
SHA-256: 82bb76a5043d159a15f8c25259a7bbd730d070998c4534ffb259eeb6da4c414c
font_02_sfnt_off000130c3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x130C3 18068 bytes
SHA-256: 1229294c52ac0fffa81d94cb986220abc41c7e070276d2a95d7b38602fa108c2