Malicious PDF — malware analysis report

Static analysis result for SHA-256 61ef88a764a0c52c…

MALICIOUS

PDF

78.3 KB Created: 2021-04-11 04:33:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-07
MD5: 9be5fe19794fdac28c545ab97b35dc76 SHA-1: 832f6cfe3da98b4651ee45b999ba4569e34fb6a1 SHA-256: 61ef88a764a0c52cd05fa5ca6fce027907b91584ee5b4ae37cab9e0da00a5623
126 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many pointing to disposable domains and structured as link farms, suggesting a phishing or malicious redirection attempt. The presence of external URIs and the overall structure indicate it's designed to lead users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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 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://www.jsif.org/sites/default/files/webform/54250685962.pdf In PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/80411930416.pdfIn PDF document text
    • http://seiary.com/sites/default/files/webform/rec/11252708720.pdfIn PDF document text
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/sumeli.pdfIn PDF document text
    • https://www.termis.org/system/files/webform/nibobuzokojovafizuza.pdfIn PDF document text
    • http://www.birdlifebotswana.org.bw/sites/default/files/webform/sightings-sketches/43600748611.pdfIn PDF document text
    • https://natsihwa.org.au/sites/default/files/webform/80931084074.pdfIn PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/pidefukil.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/25507329945.pdfIn PDF document text
    • http://www.sumnercountyhospital.org/sites/default/files/webform/72664382884.pdfIn PDF document text
    • https://www.mothercare.ro/sites/default/files/webform/resumes/28941778760.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/17232120942.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BkSY9tpko7c/uplcv?utm_term=ftb+thermoelectric+generatorPDF link annotation
    • https://thesanfordschool.asu.edu/sites/default/files/webform/87767597376.pdfIn PDF document text
    • https://ec.europa.eu/eip/agriculture/sites/default/files/webform/zuwamusijugowop.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
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dd68.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD68 5132 bytes
SHA-256: a812ba3703f04fe9cc6d274e82c7732213792e51c539854c50a965a42e9d8dba
font_01_sfnt_off0000eeb6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEEB6 12056 bytes
SHA-256: b1c90da1a764dcbda64432e83797605ef672fcbf560981462cf92748caa9dd28
font_02_sfnt_off0001177d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1177D 16036 bytes
SHA-256: ffcc099cb313ee7442755751e66ee5b466d1c2ae3a5aa4db1c7e493352985176

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