Malicious PDF — malware analysis report

Static analysis result for SHA-256 9a8328fd1c438cba…

MALICIOUS

PDF

77.0 KB Created: 2021-05-01 16:28:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 986afefcc4636981853709535def0e32 SHA-1: ac7865b73bb79fbf38ff1bd689dc9eab3c9c53c1 SHA-256: 9a8328fd1c438cba3bd98f3f1a8dafe7c1c1b1bdfd663c8f485584e05562d19f
126 Risk Score

Malware Insights

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

The PDF document contains a large number of external links, many hosted on disposable domains, indicating a link farm or SEO manipulation tactic. One of the extracted URLs, 'https://resalured.ru/strik?utm_term=dbt+therapy+nyc+sliding+scale', is flagged as unknown reputation, suggesting a potential malicious destination. The ML classifier strongly identified this PDF as malicious, supporting the link farm and potential malicious redirection.

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://resalured.ru/strik?utm_term=dbt+therapy+nyc+sliding+scale
    • https://cdn.sqhk.co/lafuwexale/RzgHshc/37664613563.pdf
    • https://purusoze.weebly.com/uploads/1/3/4/4/134495244/satipun-kuzusawogoke.pdf
    • https://cdn-cms.f-static.net/uploads/4425909/normal_606d9dad50358.pdf
    • https://cdn.sqhk.co/fujotojaxob/fYUgegd/strikers_1945_2_cheats_android.pdf
    • https://static.s123-cdn-static.com/uploads/4449629/normal_5fc9ea48aa347.pdf
    • http://vesixadaw.22web.org/sb_800_new_construction.pdf
    • http://fomilexavekol.22web.org/electric_slide_sheet_music.pdf
    • https://nemapawa.weebly.com/uploads/1/3/0/9/130969411/rovolifizotix_bikoleda_baroxapere.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://36535336-4f9e-4c0a-b1ad-3385cb5d4299.filesusr.com/ugd/15ebe2_44e63cabafab47469852b63249436413.pdf?index=true
    • https://0d555108-1732-4721-8d72-76d747b2053a.filesusr.com/ugd/1b0481_571174aefc644f959d7b687d3dd2d4d0.pdf?index=true
    • http://zuzeburim.epizy.com/55849881754.pdf
    • http://vonubopoz.rf.gd/kojiwubimi.pdf
    • https://fb7bf4c5-056f-4058-a7d1-073478569b53.filesusr.com/ugd/d90490_ba1e67c00a654b25a04d1fb2e53e50ce.pdf?index=true
    • https://807eaacf-9fb6-4e16-bcb8-061395d1d132.filesusr.com/ugd/a3ef2e_c21404a71cd74cb59200f4c9dc6312db.pdf?index=true
    • https://s3.amazonaws.com/batoragubukepo/kimudemusupokobafobegi.pdf
    • https://s3.amazonaws.com/jebokizez/covalent_bonding_practice_worksheet_answers.pdf
    • https://s3.amazonaws.com/tuxutedi/luforololonasos.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ed29.bin
83055ec54ca40db24d1291b52577d81740fe564668a8ce03c6ed8d816d1af669		 pdf-font-stream PDF embedded font (sfnt) at offset 0xED29 5576 bytes
font_01_sfnt_off0001001b.bin
29639d0fd9b9d532c277c7a564a4bd31331403b9bd0fb69aa5316d51b923c476		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1001B 11476 bytes

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