Malicious PDF — malware analysis report

Static analysis result for SHA-256 48d528c6bf89a18b…

MALICIOUS

PDF

71.7 KB Created: 2021-02-26 12:26:34 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-16
MD5: 71f75663222b62775ea8982aaa9ffaec SHA-1: de59907d1ea9b60c8d5d825c9d9babbabc21d7d5 SHA-256: 48d528c6bf89a18b0c41e7046c57f8f5ed7b33626f5b9acd85f2beed083c5917
126 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF file contains numerous embedded URLs, many of which point to disposable domains and are likely part of a phishing or link farm scheme. The ML classifier and ClamAV detection strongly indicate malicious intent, specifically phishing. The document body, though heavily obfuscated, suggests a lure related to 'teaching assistants' to direct users to malicious sites.

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://baarspo.ru/strik?utm_term=what+are+the+relevant+standards+for+teaching+assistants PDF link annotation
    • http://manuximaxemeje.scienceontheweb.net/you_win_in_the_locker_room_first.pdfIn PDF document text
    • http://tifusavegapawuf.mygamesonline.org/duxanejekusirevab.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4377100/normal_5ffc994f2d710.pdfIn PDF document text
    • https://jetapixivokob.weebly.com/uploads/1/3/4/7/134726526/bopudalusoda.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4475380/normal_6033d0960ec27.pdfIn PDF document text
    • https://nojonepidafajik.weebly.com/uploads/1/3/0/7/130775859/3499257.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4417992/normal_5fcb273b132e7.pdfIn PDF document text
    • http://rasudilikid.mywebcommunity.org/66676584021.pdfIn PDF document text
    • http://fesotisifofil.mygamesonline.org/tejolupirazu.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4393754/normal_600fc9fdeb9b1.pdfIn PDF document text
    • http://wijasagasipode.getenjoyment.net/25571753796.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4368752/normal_5fd233cd697e9.pdfIn PDF document text
    • https://jolejijiwunepa.weebly.com/uploads/1/3/5/3/135334118/tepopukajiwulag-lefunofowepu.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4367687/normal_5fc86c1a03d11.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://busimutu.epizy.com/kolupepazusatamunanareb.pdfIn PDF document text
    • http://pesetunal.onlinewebshop.net/sexofugogunejikumav.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_off0000dd4b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD4B 5356 bytes
SHA-256: 65a221b1f07f5885c05fd0cdca832bc3a098687dc69e40d04c4d982093617ac9
font_01_sfnt_off0000ef8a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF8A 9932 bytes
SHA-256: 41a85e8a5886d79457028c9ff640a1e125ed183f76586218f908144db9f3b18b

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