Malicious PDF — malware analysis report

Static analysis result for SHA-256 37a9726720da2be3…

MALICIOUS

PDF

87.5 KB Created: 2021-02-21 03:26:45 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-16
MD5: 4a33965550e5facad4df6ff2fabab2a5 SHA-1: 25a8a2bd0c59bfc6ac7be4ae4006f2e907c8cd77 SHA-256: 37a9726720da2be311f312ee3639c149218bc37df27baf960b3be835f95c5f5c
126 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

This PDF file was flagged as malicious by ML classifiers and ClamAV, indicating a phishing or trojan threat. It contains numerous embedded URLs, with at least one pointing to a suspicious domain ('crophysi.ru') and another to a link farm ('cdn.sqhk.co'), suggesting an attempt to redirect users to malicious content. The document body, though heavily obfuscated, contains text related to 'trigonometry formulas' and 'wkhtmltopdf', which may be a lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://crophysi.ru/123?utm_term=trigonometry+formulas+for+class+10+ssc PDF link annotation
    • https://cdn.sqhk.co/jarixizotib/Wgdpfij/best_free_football_live_score_app.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4387715/normal_5ffe71af0ff23.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4485821/normal_5ffd80b69c9e2.pdfIn PDF document text
    • https://cdn.sqhk.co/kapapomabu/dC7VheX/age_of_fantasy_guide.pdfIn PDF document text
    • https://cdn.sqhk.co/zetanitanedo/Bhjdhji/mubedubedoz.pdfIn PDF document text
    • https://cdn.sqhk.co/tunuzasana/ich8jjh/hidden_mystery_games_y8.pdfIn PDF document text
    • https://cdn.sqhk.co/tunuravaxoxi/8hchgQr/duvogipedomugipipasapi.pdfIn PDF document text
    • http://hookup154.online/crossy_road_secret_characters_arctic_update7t8vt.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4464297/normal_5fc95d901130f.pdfIn PDF document text
    • http://vashmaster.info/counting_1-_10_worksheets_kindergartenag4tu.pdfIn PDF document text
    • https://cdn.sqhk.co/luwagoma/08ieihX/35909704731.pdfIn PDF document text
    • http://kukushka.space/davis_laboratory_and_diagnostic_testsy138x.pdfIn PDF document text
    • http://uaportal.site/41864660679xc9gz.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4470960/normal_6019f0c2df0d8.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/bejexe/5176368934.pdfIn PDF document text
    • https://s3.amazonaws.com/zesotat/98343063111.pdfIn PDF document text
    • https://s3.amazonaws.com/befafuni/3_4_view_nose_drawing.pdfIn PDF document text
    • https://s3.amazonaws.com/wuwabobujasivor/piano_fur_elise_sheet_music.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
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_004_off0001243c.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1243C 24892 bytes
SHA-256: e946646d06f0db69f4a723165940054b460a51902d1110cdbe6e0fe6e519d73f
font_00_sfnt_off0000eac3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEAC3 5444 bytes
SHA-256: 5580d2fba30199cb23a13f2962e3d12369c630a6bc0af52763e698949822b2c6
font_01_sfnt_off0000fd44.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD44 11364 bytes
SHA-256: 00b7a2a900ca49c366bba0b3d661963c08c3546b4ba01d752ffb3d112231a98d

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