Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4839ccc0b40df7b…

MALICIOUS

PDF

77.5 KB Created: 2021-03-22 18:17:58 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: 4238b653f92db64501d166bb272c0309 SHA-1: ce964527fee49102c5484d1b8caf3cddb9fc0abc SHA-256: b4839ccc0b40df7b3987f3922d6d21dc8bd05a5d6091a5a98267fa47d2f06077
126 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, with one specifically pointing to 'jacksth.ru' and a query parameter suggesting a lure related to Arduino pin charts. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a pattern of using disposable hosting for link farms, further supporting a malicious intent. The ML classifier and ClamAV detection strongly indicate malicious content, likely for phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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=arduino+nano+pin+chart PDF link annotation
    • http://creditscorefix.info/chicago_style_citation_example_footnotesippm4.pdfIn PDF document text
    • http://shmelev.pro/mumbo_jumbo_ishmael_reedg3mct.pdfIn PDF document text
    • http://sfr-espace.best/financial_accounting_in_an_economic_contextbvf34.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4423136/normal_6055882424bcc.pdfIn PDF document text
    • http://krokoboko6.xyz/photoshop_brushes_free_paint_splashpqh3b.pdfIn PDF document text
    • http://meetchat.space/city_ward_mapbc398.pdfIn PDF document text
    • http://iqecoportal.ru/fopemamodimif7oy39.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4405467/normal_604b864780e73.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4464311/normal_60570ea622561.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4388160/normal_6049ecf453ba6.pdfIn PDF document text
    • http://freefire-gifts.com/fuwibuvup381tv.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/b450da22-7857-40c6-bff0-6dc905215474/javascript_reference_variable_in_object.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/e2a8e7f6-7e31-49e3-929f-51b5860c0426/1950108550.pdfIn PDF document text
    • https://23da7c74-6e14-424a-b22a-901aa35eafb1.filesusr.com/ugd/9cc572_99039c0efc9944809a5e5b415c18f265.pdf?index=trueIn PDF document text
    • https://b8f7bc2e-5f90-466c-a76c-b8215bfdb3ae.filesusr.com/ugd/9717d9_dde7d0c0867f441d87da316a8bc807c0.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/4ca101f9-0ef3-4f37-979c-29a5b493e92b/64014026935.pdfIn PDF document text
    • https://69a21580-3c80-4f81-8097-1ec0bc18215d.filesusr.com/ugd/bd7df1_f8b292b4a92f45eebbb7be2c1e9be18a.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/kuboki/venufuzewonidoriwatok.pdfIn PDF document text
    • https://b998fa74-583e-446a-a2a7-67f41460fdb2.filesusr.com/ugd/e081f8_60afba1a80b24e06b4b74d739a38a361.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/824411bc-e365-4bb7-be7a-e881b480831a/17658217155.pdfIn PDF document text
    • https://s3.amazonaws.com/gofiguj/future_of_electric_vehicles_in_india.pdfIn PDF document text
    • https://023e3b0e-89aa-4e00-bd19-175c11a0a9c0.filesusr.com/ugd/5f4883_7dcb9011cac749e7afddb0a927e5fa20.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/e5bb105b-5c91-439b-a86d-405beda2ebcd/what_is_knowledge_worker_in_nursing.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_off0000f368.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF368 4940 bytes
SHA-256: 160aac4a625e5c96df5b840a519322b0b44316dcaaed059511a1823a850e8661
font_01_sfnt_off00010432.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10432 10668 bytes
SHA-256: c0124b11765d3580924a8e7abc5c316d9f6cac3b7f635bc37b4b11e02c541baf