Malicious PDF — malware analysis report

Static analysis result for SHA-256 c528bb58d6c01a5e…

MALICIOUS

PDF

74.2 KB Created: 2021-02-15 18:19:08 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-23
MD5: 1bfa7cafdc32843cf5c86ffcb43a86eb SHA-1: aef877ad0da2766e8f9b6f6cdcce708153ff5cd1 SHA-256: c528bb58d6c01a5e62ef5b1137d80bbd091563397ccd1230226f67a0b29b5a45
126 Risk Score

Malware Insights

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

The PDF file is flagged as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous external URLs, many of which are hosted on disposable domains or redirectors, suggesting a link farm or phishing operation. The document body, though heavily obfuscated, contains metadata suggesting it was generated by wkhtmltopdf, and the presence of embedded URLs points towards an attempt to redirect users to malicious sites for further exploitation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://jacksth.ru/strik?utm_term=introduction+to+cryptography+with+coding+theory+pdf PDF link annotation
    • https://cdn.sqhk.co/letijefa/agcijgg/siren_head_horror_game_unblocked.pdfIn PDF document text
    • https://pirovosarelivo.weebly.com/uploads/1/3/1/4/131406751/6b9ab4026a1.pdfIn PDF document text
    • http://grafoanaliz.ru/how_to_put_copyright_on_websitedf56u.pdfIn PDF document text
    • http://cookwellbakewell.com/tuwidezolimaroxakugodopw9xt.pdfIn PDF document text
    • http://20970907.net/valoracion_neurologicakjt2s.pdfIn PDF document text
    • http://idealica-italiaufficiale.site/36185377019p6q0a.pdfIn PDF document text
    • http://brettlockhart.com/13725526966qgrmn.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/zuxime/pumped_up_kicks_piano_sheet_music.pdfIn PDF document text
    • https://s3.amazonaws.com/davubewu/archero_guide_talents.pdfIn PDF document text
    • https://s3.amazonaws.com/welanisowari/74414068560.pdfIn PDF document text
    • http://sigedasubaduvep.rf.gd/22898596939.pdfIn PDF document text
    • http://luwegovufa.epizy.com/geometric_shapes_worksheets_for_1st_grade.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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d8ee.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD8EE 3036 bytes
SHA-256: 225903e2633627bfcc1f0c562903e307ced3cc2e3138bae544ee9efd29b8e952
font_01_sfnt_off0000e3bc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3BC 5340 bytes
SHA-256: 836cf871063b886748ec577c92305b50830cac86a1042f0205ed3d4e029930a4
font_02_sfnt_off0000f5fe.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5FE 10996 bytes
SHA-256: c86a9b7a0409f4a7d1e8497380f7ab2c43353e53fe13790241ed8d9bc415f618

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