Malicious PDF — malware analysis report

Static analysis result for SHA-256 8c31eb865220d338…

MALICIOUS

PDF

78.0 KB Created: 2021-05-02 14:22:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: c71286228beaeec97f2b86572a5a52cd SHA-1: c9a884be3a9a856b0f654b9b6279111b2a43d061 SHA-256: 8c31eb865220d338e984028bce0b7befcf69d5e3f82fb4932c0007c2cf536aab
186 Risk Score

Malware Insights

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

This PDF document contains a large number of external links, many hosted on disposable domains, suggesting it is part of a link farm or SEO manipulation scheme. The ClamAV detection and ML classifier strongly indicate malicious intent, likely phishing or malware distribution. While no scripts were explicitly extracted, the PDF structure and heuristic firings point towards the use of embedded JavaScript to facilitate redirection to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://fokemale.ru/strik?utm_term=how+to+harvest+butter+crisp+lettuce PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4391001/normal_606422ecabc64.pdfIn PDF document text
    • https://wikifepum.weebly.com/uploads/1/3/3/9/133986434/vugimuregoliwo.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4388596/normal_6010c59dda0d5.pdfIn PDF document text
    • http://nafarami.medianewsonline.com/vozebusipupuzalupave.pdfIn PDF document text
    • http://dotixomovi.sportsontheweb.net/77320866764.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4418566/normal_5fecb05e63d06.pdfIn PDF document text
    • http://davupopebuwiser.sportsontheweb.net/12_steps_download.pdfIn PDF document text
    • https://dasowafajego.weebly.com/uploads/1/3/4/7/134723411/weserowuramas.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/debiwelof/does_arbys_have_french_fries.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/ac491854-ac98-4e52-8da5-91576a83cd86/26679318033.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/ff12c558-03b0-4290-8f1c-912960be0d39/genie_gs_1930_parts_list.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/fe28b628-8d32-43a0-8f45-d50a9bd8e252/bose_acoustimass_10_series_iii_home_theater_speaker_system.pdfIn PDF document text
    • https://s3.amazonaws.com/diwitapezu/xopebajapo.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4c04042e-e16e-4cd3-b08d-21d1dc409b46/ronejez.pdfIn PDF document text
    • https://s3.amazonaws.com/toliwudalamem/99386126769.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/bd162511-1935-40bc-9de0-9af98510e1a1/short_film_scripts_on_drug_addiction.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/b5d8bbc6-3efd-419f-aec9-669b5e4d4b90/danby_dehumidifier_ddr060becwdb_reviews.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/50d3bab0-d14d-417d-839f-71cde2e168e6/31556973189.pdfIn PDF document text
    • https://s3.amazonaws.com/wibedubosateg/66370451705.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/20568638-f751-446b-96b8-d9b9f277fcef/64183315797.pdfIn PDF document text
    • https://s3.amazonaws.com/dowesitobuga/bcbs_federal_prior_authorization_form_for_surgery.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_off0000f3de.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF3DE 5276 bytes
SHA-256: 1cb155ad04d3ac3db5306e0b18040767341da19d0b956c6d71bc667d43cec9f7
font_01_sfnt_off000105dc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x105DC 10832 bytes
SHA-256: d0d14ff760779cc4731c55ce27e0edf6c24c2ad45e5547d92f554f42508f5333