Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef51d357706068be…

MALICIOUS

PDF

69.6 KB Created: 2021-09-27 20:02:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-22
MD5: 260fb0d9ca46cbba4d7dbd1a5d617fb3 SHA-1: 5981d620da86a3d8d4493a4a1ad29e9167e2615a SHA-256: ef51d357706068bec759fc60be22e447efc6cb281752580b21a6d1d39d03fda1
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains a large number of embedded URLs pointing to various domains, suggesting a link farm designed to redirect users to malicious content. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly indicates this purpose. While no scripts were explicitly extracted, the nature of the PDF and its numerous external links point towards a phishing or malware distribution attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://ketchas.ru/uplcv?utm_term=wpa+wps+tester+mod PDF link annotation
    • http://linhkienhunganh.vn/luutru/files/zagofidaku.pdfIn PDF document text
    • http://dunakeszi.varosom.hu/userfiles/files/33360558340.pdfIn PDF document text
    • http://color-gateway.com/userfiles/file/77863315177.pdfIn PDF document text
    • https://kientrucqhouse.com/uploads/image/files/pozimepuxotajimo.pdfIn PDF document text
    • https://srccaa.bdbabymart.com/app/webroot/ckfinder/userfiles/files/7803959505.pdfIn PDF document text
    • http://www.c-l-r-p.com/admin/ckfinder/userfiles/files/jipobiviku.pdfIn PDF document text
    • http://kortennis.co.kr/B/ck/ckfinder/userfiles/files/vobipakeveduxuwomigijid.pdfIn PDF document text
    • https://sayurhijau.com/contents/files/69259472581.pdfIn PDF document text
    • https://nisahanpin.com/calisma2/files/uploads/vapaxomuvelamukirorajij.pdfIn PDF document text
    • https://chasehr.in/userfiles/file/78323014944.pdfIn PDF document text
    • https://lajovisena.com/gallery/file/larozonorazufafulagefe.pdfIn PDF document text
    • https://pediatricpotentialsnj.com/PP/PPpng/files/kanudisexujenisewu.pdfIn PDF document text
    • https://alfa-clining.ru/wp-content/plugins/super-forms/uploads/php/files/dc8c8ed123ec4968d31a7eefb1ce38e2/zarazogawuremotuke.pdfIn PDF document text
    • https://etre-cheval.fr/Applications/MAMP/htdocs/etre%20cheval/news_pix/file/deribuse.pdfIn PDF document text
    • https://bda.ch/ckfinder/userfiles/files/kalefe.pdfIn PDF document text
    • https://apskarota.org/userfiles/file/19357021055.pdfIn PDF document text
    • http://solamsys.com/userData/board/file/18081335950.pdfIn PDF document text
    • https://perfecthospitals.org/ckfinder/userfiles/files/zakexozopigezaxuzi.pdfIn PDF document text
    • http://chaputlawoffice.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/defuzimoropakemowaz.pdfIn PDF document text
    • http://homeshopeez.com/uploaded_files/userfiles/files/28969196888.pdfIn PDF document text
    • http://bluelakehomestay.com/uploads/image/files/51627382599.pdfIn PDF document text
    • 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_off0000ad95.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAD95 10388 bytes
SHA-256: e5b9a9f1804728f14b1d45de9e3e70e4c0e4dda9bd707473fb5b2ae74b6f4c78
font_01_sfnt_off0000c53d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC53D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000dd4f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD4F 17476 bytes
SHA-256: 1e357d07bf435d91c44331e30e64c16b130ee0eb687606881b9c2d630b4ead60