Malicious PDF — malware analysis report

Static analysis result for SHA-256 23c0811f75541ef3…

MALICIOUS

PDF

75.7 KB Created: 2021-02-23 19:30:14 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: 73785a4678c4e71aa98307aa2dfc55d8 SHA-1: a5842a488670b6def12561312f99a5d90a8708cf SHA-256: 23c0811f75541ef33242507c8f14b5b566ea701ee6901953f3e75884b235b21e
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file contains a large number of external links, many pointing to disposable domains and hosted on services like weebly.com and cdn.sqhk.co. This behavior is characteristic of SEO link farms or distribution points for further malicious content. The ML classifier strongly indicated maliciousness, and the PDF structure with numerous external URIs supports this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://maypoin.ru/123?utm_term=exerpeutic+folding+exercise+bike+australia PDF link annotation
    • https://cdn.sqhk.co/wareberefiz/bgfhjgc/tattoo_sleeve_maker_online.pdfIn PDF document text
    • https://cdn.sqhk.co/tosijoxopum/ZjdZhxC/80s_songs_hits_list.pdfIn PDF document text
    • http://cleaner-inn.club/42342262209kl51f.pdfIn PDF document text
    • http://idclick.cash/golf_battle_online_spielen2oq3f.pdfIn PDF document text
    • http://vorecan.space/59808749905n8wvg.pdfIn PDF document text
    • https://revugegan.weebly.com/uploads/1/3/4/6/134682990/ziruvem-dojibawifarila.pdfIn PDF document text
    • https://cdn.sqhk.co/labifikup/gcJMIzO/kabosomabula.pdfIn PDF document text
    • https://cdn.sqhk.co/busibelifiv/jafNpZH/dugagiredakiruzukuw.pdfIn PDF document text
    • http://rankingcoach-apps.com/medicina_fisica_y_rehabilitacion_krusenyix6p.pdfIn PDF document text
    • https://dutosagow.weebly.com/uploads/1/3/0/7/130775111/lawelelunitoroxadofa.pdfIn PDF document text
    • https://zoxuzuxebexot.weebly.com/uploads/1/3/0/9/130969059/mibiloju.pdfIn PDF document text
    • https://cdn.sqhk.co/xavaxonad/ggjjgOp/dumebotipukazaviniradixa.pdfIn PDF document text
    • http://rodsfish.club/hp_officejet_5610v_all-in-one_ink_cartridgev5i5y.pdfIn PDF document text
    • http://psychologyrelax.xyz/16036323686uv9ck.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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_off0000ea40.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA40 5552 bytes
SHA-256: 2dc5888fb4f99e5aa2300dff864b19270e3e36d7a700739cf082d66df7ce727e
font_01_sfnt_off0000fd35.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD35 10836 bytes
SHA-256: 0130a2f0aef7d5fea35296de29a81aceb9b0a2d4773b09c7be21f8df878e3bfa

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