Malicious PDF — malware analysis report

Static analysis result for SHA-256 39af4a16635bc9f9…

MALICIOUS

PDF

91.9 KB Created: 2021-09-12 07:46:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: dd68fd51e438298ced1fb5695a09c922 SHA-1: 7ebf5d739d5cbaeb67fedccc418532599d676604 SHA-256: 39af4a16635bc9f94d6db2fa55a27c2a6e54ed7e15d91df74fee90092418f4ac
134 Risk Score

Malware Insights

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

The sample is a PDF file flagged by ML classifiers and ClamAV as malicious. It contains embedded JavaScript and numerous external URIs, many of which are part of a link farm hosted on disposable domains. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a tactic to obscure the true destination by using multiple distinct hosts with few links per host. The embedded JavaScript likely facilitates the redirection or download process, contributing to the phishing and malware delivery attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9970

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
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://ubest.ru/images/file/93424540521.pdf In PDF document text
    • https://www.barrau-philippe-sedeco.fr/ckfinder/userfiles/files/gobidupuwutesewezo.pdfIn PDF document text
    • https://bunyaminerdemir.com/resimler/files/siragabububozat.pdfIn PDF document text
    • https://dveropolis.ru/upload_picture/xuxojuwepam.pdfIn PDF document text
    • https://www.rougeindigo.com/ckfinder/userfiles/files/52400397861.pdfIn PDF document text
    • https://www.iieng.org/editor/ckfinder/userfiles/files/sonozexukefeligep.pdfIn PDF document text
    • https://fratellifurloni.it/file/bajozorusar.pdfIn PDF document text
    • http://dralituncer.net/userfiles/file/27809723089.pdfIn PDF document text
    • http://allier-genealogie.org/File:/22658629837.pdfIn PDF document text
    • https://minjar.mebel18.com/uploads/files/samogegumumikukizuxosuk.pdfIn PDF document text
    • https://laetitiabernard.fr/images/file/xiterobodupajodasilim.pdfIn PDF document text
    • http://precisao.net/files/files/lalekexidufos.pdfIn PDF document text
    • https://nguyenvanhuongloc.vn/app/webroot/files/images/pages/files/23613783127.pdfIn PDF document text
    • http://apple888.vn/luutru/files/56189189900.pdfIn PDF document text
    • https://hankilfood.com/upfile/files/23267763660.pdfIn PDF document text
    • http://conservativista.com/js/ckfinder/userfiles/files/22993699018.pdfIn PDF document text
    • https://kga-am-adlergestell-ev.de/kga/ckfinder/userfiles/files/10848712885.pdfIn PDF document text
    • http://honghuibio.com/d/files/3412123159.pdfIn PDF document text
    • http://ardeche.proximeo.com/ckfinder/userfiles/files/pibitudidudosokitenesodib.pdfIn PDF document text
    • http://atlantichomeportugal.com/wp-content/plugins/formcraft/file-upload/server/content/files/161361418379af---bakujedut.pdfIn PDF document text
    • http://bjoybrands.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613383d0573fc---jumugogat.pdfIn PDF document text
    • https://bazk.info/public_htmluploads/file/zuzodorologivapogij.pdfIn PDF document text
    • http://sukhonthip.com/file_media/file_image/file/42589378750.pdfIn PDF document text
    • https://amzentransportationindustries.com/admin/imagetemp1/file/ronutokiwapatukenegazi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BkSY9tpko7c/uplcv?utm_term=file+iso+windows+10+64+bitPDF 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_off0000e935.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE935 17048 bytes
SHA-256: 41cb43d6e4b4a0841fe865e4c87782e95753462645c2edd528cbd507bf4ad5aa
font_01_sfnt_off00011531.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11531 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012d48.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12D48 19784 bytes
SHA-256: 5814843724365023f9319995a73ad158da946ba88e7825f3f610c167581a43ee