Malicious PDF — malware analysis report

Static analysis result for SHA-256 4bcb999f78303173…

MALICIOUS

PDF

86.2 KB Created: 2021-09-16 05:17:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 7711893b638af4a761ce6253326855c1 SHA-1: b3dec21b30042f75255c6691444becb4e4320fce SHA-256: 4bcb999f78303173098f5e813edd340d8e70a200a86419f99ee26687f2247b20
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ML classifiers and ClamAV as malicious. It contains numerous embedded URLs, many of which are part of a link farm hosted on disposable domains, suggesting a phishing or malware distribution attempt. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic specifically indicates a non-clustered link farm on disposable hosting, reinforcing the malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://oniceh.ru/uplcv?utm_term=dating+my+daughter+mod+apk PDF link annotation
    • https://denizlihorozu.com/resimler/files/fasobiviroraze.pdfIn PDF document text
    • http://sushrutproctology.org/ckfinder/userfiles/files/xefalixadituminu.pdfIn PDF document text
    • http://chieusangducphat.com/uploads/userfiles/file/32908715990.pdfIn PDF document text
    • http://tkhomedeco.com/assets/uploads/ckedit/files/20210911023133.pdfIn PDF document text
    • https://www.tifdip.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c09d5cbbbf---89599999309.pdfIn PDF document text
    • https://webmenuplus.com/images/file/18983269043.pdfIn PDF document text
    • http://www.maoles.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613577d5d02bd---17191751240.pdfIn PDF document text
    • https://suthuytinh.com/app/webroot/uploads/files/zeluluzo.pdfIn PDF document text
    • https://a-guskov.ru/uploads/files/13613984278.pdfIn PDF document text
    • https://krusomying.com/data/file/naxuluwogazaginatutira.pdfIn PDF document text
    • https://wintechindia.in/ckfinder/userfiles/files/naxakidifitewekaboviwur.pdfIn PDF document text
    • https://bataretak.com/img/files/file/xufakuwukaruzawekug.pdfIn PDF document text
    • http://www.rosabrockenhaus.ch/ckfinder/userfiles/files/27983282264.pdfIn PDF document text
    • http://dorrstrechy.cz/UserFiles/File/64035913633.pdfIn PDF document text
    • http://www.macrolepidoptera.hu/userfiles/files/97291980611.pdfIn PDF document text
    • http://workcoop.org/fckeditor/userimages/file/20210901111306.pdfIn PDF document text
    • http://villabrown.it/userfiles/files/gijozoko.pdfIn PDF document text
    • http://xn--oy2b19v1mb1yi.com/userfiles/file/dukugi.pdfIn PDF document text
    • http://arsvet.ru/img/upload/76175036772.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_off0000eaeb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEAEB 18452 bytes
SHA-256: 2ba5b053d2913408096ed6f04b4644a9e4e3324620e7207af059b7d3c1de75d1
font_01_sfnt_off00011a59.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A59 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013270.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13270 10932 bytes
SHA-256: 96a03186bb9f2ca58865d5f47a1ed067ee885506a6335d6116d8aebba0bc7c75

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