Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4dc1ed34b9b8c21…

MALICIOUS

PDF

71.1 KB Created: 2021-02-24 13:25:53 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-20
MD5: 8287abe79f628873a513430556396406 SHA-1: d819de95f5b9e6ef472e64021a3b7afc9ac71147 SHA-256: a4dc1ed34b9b8c2129b880001c3bbc1f2ccfa93dcb04205fd1c7392eec49c5fb
126 Risk Score

Malware Insights

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

The PDF file is identified as malicious by ML classifiers and ClamAV, and exhibits characteristics of a link farm on disposable hosting. The document body, though heavily obfuscated, suggests a lure related to SAT math preparation, directing users to multiple external URLs, including suspicious domains like seumenha.ru and fb-ig-violation.com. The presence of embedded URLs and the heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly indicate a phishing or redirection attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://seumenha.ru/123?utm_term=how+to+get+better+at+math+for+sat PDF link annotation
    • http://fb-ig-violation.com/tujuwtgkk9.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4462339/normal_5ff8b5fa051c6.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4408718/normal_5fcf2587aada4.pdfIn PDF document text
    • http://biweekamnf.com/eeg_report_timee4ym5.pdfIn PDF document text
    • http://reduslim-sito.site/age_of_empires_castle_siege_android_requirementsu5b95.pdfIn PDF document text
    • http://belkwigs.com/fadasxbsh1.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4392664/normal_602e333f12622.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4374860/normal_600a90c0a8a9d.pdfIn PDF document text
    • http://rexasokozeg.iblogger.org/lizufedovirufuxut.pdfIn PDF document text
    • http://xopidufixa.iblogger.org/niweniwujikimirobabonukav.pdfIn PDF document text
    • http://sbrf.link/kolabova2p2bd.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://wuzatefiroko.epizy.com/caddra_guidelines_2018.pdfIn PDF document text
    • https://s3.amazonaws.com/magapeguwabe/carbohydrates_biology.pdfIn PDF document text
    • https://s3.amazonaws.com/zesotat/wejuxedozoboferov.pdfIn PDF document text
    • https://s3.amazonaws.com/wewuxuviwar/nujebilosunowozago.pdfIn PDF document text
    • https://s3.amazonaws.com/gapivegek/new_pulmonary_hypertension_guidelines_2018.pdfIn PDF document text
    • http://dolifusekaxug.epizy.com/padinemodet.pdfIn PDF document text
    • https://s3.amazonaws.com/fofeguj/how_to_get_yeti_microphone_to_work.pdfIn PDF document text
    • https://s3.amazonaws.com/ronenitevodo/download_light_novel_danmachi_indo.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_off0000d968.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD968 5340 bytes
SHA-256: 6e62c7fb32abf6a6cb976eb052d86fa3a87267deb923810530f3557376f14ec3
font_01_sfnt_off0000eb83.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB83 10352 bytes
SHA-256: 71a917b18da83130331fe44c5818a49bbdec88bf1556bc093ea288f324b3b136

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