Malicious PDF — malware analysis report

Static analysis result for SHA-256 31ab437db7af8004…

MALICIOUS

PDF

74.2 KB Created: 2021-02-10 05:18:22 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: 8e1a12d0557f5ffb83a5ad80df3518b5 SHA-1: 48f85cbdbecaaa84da949803c100ff6fd4cc3505 SHA-256: 31ab437db7af80049598e142e92df79a5ac01ba44e60fc998956821bc56d6437
126 Risk Score

Malware Insights

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

The PDF file contains numerous embedded links, many pointing to disposable domains, suggesting a phishing or link-farming attempt. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' and the high ML score indicate malicious intent. While no scripts were explicitly extracted, the presence of embedded URLs and the nature of the heuristics strongly suggest a phishing lure, likely delivered as a spearphishing attachment.

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://leonvi.ru/wb?keyword=off%20balance%20sheet%20definition PDF link annotation
    • https://static.s123-cdn-static.com/uploads/4411512/normal_5ffeb1eae4b6c.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4367914/normal_5fcff3e8c8d45.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4366317/normal_5fe0687259ce5.pdfIn PDF document text
    • http://xinupavob.iblogger.org/44497251171.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4476443/normal_5fe8b80f8d803.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4458125/normal_5ffba08c26df4.pdfIn PDF document text
    • http://xuzekamusudis.iblogger.org/biweekly_pay_schedule_template.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://savagit.rf.gd/invitation_letter_for_china_visa_template.pdfIn PDF document text
    • https://s3.amazonaws.com/nuxulikiwab/english_premier_league_fantasy_cheat_sheet.pdfIn PDF document text
    • http://fopekexu.epizy.com/mail_alice_su_android_problemi.pdfIn PDF document text
    • http://felobiziwikegu.rf.gd/abbreviations_list_for_competitive_exams.pdfIn PDF document text
    • http://jifusewu.epizy.com/1731505202.pdfIn PDF document text
    • http://vonupov.epizy.com/perfect_squares_worksheet_1_20.pdfIn PDF document text
    • http://zexolaxew.epizy.com/cfcc_financial_aid_forms.pdfIn PDF document text
    • https://s3.amazonaws.com/xamibudasagas/21357700344.pdfIn PDF document text
    • https://s3.amazonaws.com/lokijuronig/ct_brain_anatomy_radiology.pdfIn PDF document text
    • http://kosuvoz.epizy.com/android_studio_create_shortcut_linux.pdfIn PDF document text
    • http://vefapiba.epizy.com/exercise_3_sentence_completion_lesson_6_answers.pdfIn PDF document text
    • http://nopexuwub.rf.gd/vaaste_female_ringtone_mr_jatt.pdfIn PDF document text
    • https://s3.amazonaws.com/midizaxopazeji/76740479031.pdfIn PDF document text
    • http://bowukedogatowo.epizy.com/incident_report_sample_in_workplace_doc.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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e4be.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4BE 5180 bytes
SHA-256: 97cd1cf31d0515c5b8fea735f587c4ce2079d2de738e37b0acb54d19cd9f413f
font_01_sfnt_off0000f656.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF656 10940 bytes
SHA-256: e38475cc3d8508c378346f366a25d316cfca604dbc77baaf26fe6233c4c86646

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