Malicious PDF — malware analysis report

Static analysis result for SHA-256 3e20992b5b5aeddb…

MALICIOUS

PDF

73.6 KB Created: 2021-04-20 06:12:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: 0e8d599d7966a3ccef72e4384a8646d2 SHA-1: b311aa7a23240385d074181871a7d4912d2ab407 SHA-256: 3e20992b5b5aeddbae92db4210b2b9265388d164e4e942e1c2f09d7046fa09ed
126 Risk Score

Malware Insights

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

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, suggesting a link farm designed to redirect users. The document body, though heavily obfuscated, contains references to wkhtmltopdf and a date, indicating it was likely generated programmatically to appear as a legitimate document, such as a guide on creating bubble answer sheets, to entice clicks on malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

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.a1touchsolution.nl/sites/default/files/togivem.pdf In PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/ponezilineg.pdfIn PDF document text
    • https://www.jsif.org/sites/default/files/webform/vinuriruxelapaviwona.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/tekuxegejarikuferibo.pdfIn PDF document text
    • https://www.pharoxglobal.com/sites/default/files/webform/zomufajiwadusepa.pdfIn PDF document text
    • http://www.birdlifebotswana.org.bw/sites/default/files/webform/sightings-sketches/lewuxevibonotokezesa.pdfIn PDF document text
    • https://www.mothercare.ro/sites/default/files/webform/resumes/77861868930.pdfIn PDF document text
    • https://natsihwa.org.au/sites/default/files/webform/80931084074.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/zabufenopi.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/93854264345.pdfIn PDF document text
    • https://www.dgs-interparts.be/sites/default/files/7838369457.pdfIn PDF document text
    • http://spotlight-sites.com/sites/default/files/webform/sizewavajifur.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/Uplcv/~3/LPIa9PGmDLg/uplcv?utm_term=how+to+make+a+bubble+answer+sheet+in+wordPDF link annotation
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/8342566550.pdfIn PDF document text
    • https://www.healthdata.org/sites/default/files/resumes/fanonexujezurexuli.pdfIn PDF document text
    • https://gradfutures.princeton.edu/system/files/webform/16157352895.pdfIn PDF document text
    • https://drones.princeton.edu/system/files/webform/voretazejujuwewoz.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_off0000e4c1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4C1 5324 bytes
SHA-256: 5d8840d4d3cc9f8454796afc5467ec2ec82ff7089b71ddcf2401003a700a0f91
font_01_sfnt_off0000f6b2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6B2 10200 bytes
SHA-256: c8d08eb6fa4b000e14cf8c0a9a8e556389b50616666963bfdbc398c12feb4cfe

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