Malicious PDF — malware analysis report

Static analysis result for SHA-256 bcf9e5d495fc35cf…

MALICIOUS

PDF

82.5 KB Created: 2021-09-19 06:03:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: db22165586ef4633111edebd5898bc81 SHA-1: 5e6780164d05ee3a7f7d99ec79317e2c59720519 SHA-256: bcf9e5d495fc35cf50cca65324bd0cbd1b22be416275e85278920d78a458d11c
216 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by a ClamAV signature and an ML classifier, and it contains heuristics indicating it's a link farm and a lure for recovery secrets. The embedded URLs, while some are marked benign, are part of a pattern often used in phishing or credential harvesting schemes. The document body is heavily obfuscated, preventing a direct analysis of its content, but the heuristics strongly suggest a social engineering attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Recovery secret / private key request critical SE_SECRET_RECOVERY_LURE
    Document requests recovery phrases, private keys, backup codes, or saved passwords. Requests for these secrets in a document are high-risk.
  • 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 https://tylbm.com/Upload/ckeditor/files/62041071163.pdf In PDF document text
    • https://claphamjunction.com.au/wp-content/plugins/super-forms/uploads/php/files/c9ad3bc9a6dd3f5a9e7f625c14be1481/mekalezugu.pdfIn PDF document text
    • http://www.globalnautique.nl/upload/files/55656703056.pdfIn PDF document text
    • https://www.anoregmt.org.br/ckeditor/ckfinder/userfiles/files/8765310763.pdfIn PDF document text
    • http://tsrmmessina.it/userfiles/files/seninukomip.pdfIn PDF document text
    • http://www.sintsprev-ms.org.br/ckfinder/userfiles/files/37851146915.pdfIn PDF document text
    • https://egokituz.eus/files/galeria/files/71786708726.pdfIn PDF document text
    • http://cn-daomeng.com/upload/userfiles/files/87c7a5a8acb8258cfc09232af651729d.pdfIn PDF document text
    • http://everestlodgelukla.com/userfiles/file/vumiwunaroxepigifelifukux.pdfIn PDF document text
    • http://eventologia.com/userfiles/files/87966616235.pdfIn PDF document text
    • http://kalkulacka-hypo.cz/userfiles/files/tapagavikuludine.pdfIn PDF document text
    • http://4chan.ro/UserFiles/file/83372651162.pdfIn PDF document text
    • http://emachn.com/data/attachment/file/69985036533.pdfIn PDF document text
    • https://cosonnguyenthanh.vn/webroot/userfiles/files/67821647319.pdfIn PDF document text
    • http://airmon.hu/images/files/vuxufu.pdfIn PDF document text
    • http://peoplefineart.com/assets/202109/files/20210909202001844853.pdfIn PDF document text
    • http://2446665a.ru/ckfinder/userfiles/files/tubigagadawax.pdfIn PDF document text
    • http://snnet.kr/board_pds/fckeditor/2021/09/file/35612225817.pdfIn PDF document text
    • http://zsdbiopharm.com/upload/files/gamatizewekeroto.pdfIn PDF document text
    • http://xn--42-jlclgg6a3e.xn--p1ai/userfiles/file/xejero.pdfIn PDF document text
    • http://visit-pune.com/userfiles/file/1170916850.pdfIn PDF document text
    • https://stefandes.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613fcb895414c---44241056110.pdfIn PDF document text
    • https://skyfireconsulting.com/wp-content/plugins/super-forms/uploads/php/files/2oauf0qni58l3eqiv0vrk5dk18/34840639706.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=identity+and+anonymous+identity+wifiPDF 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_off0000de3b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE3B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f64d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF64D 17420 bytes
SHA-256: e3cadfced33d0dc6124b8db27c2a6eb75ba53f3976cfd89cf1be0aa7303c745a
font_02_sfnt_off000123db.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x123DB 10620 bytes
SHA-256: 344f1f7079414ca015e2a928a852b42f403117ddf6d29331901081a4503e86f7

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