Malicious PDF — malware analysis report

Static analysis result for SHA-256 b9262cf5da381b71…

MALICIOUS

PDF

74.4 KB Created: 2021-04-15 18:53:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-24
MD5: 9bbdc2197d470021835ed7fc85d9f348 SHA-1: 8ede72d5f3cb1a42155c4bcffeb4a73e6e0f51a4 SHA-256: b9262cf5da381b71c424a44c3511840c291f7b01e95194d9230d2cb2cac03815
126 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, with one heuristic identifying it as a link farm on disposable hosting. The document body, though heavily obfuscated, appears to be related to a book title, potentially serving as a lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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 http://klm3fg.grhosting.cz/sites/default/files/webform/files/kokibilelage.pdf In PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/basolidigululaba.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/71502920023.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/dagen.pdfIn PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/51131620028.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/kanuvanirarotugawabu.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/palepipob.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/bemefunojupupik.pdfIn PDF document text
    • https://www.jwico.com/sites/default/files/webform/66271497470.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/sidetarebuw.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/~3/3CAf4wW3hvY/uplcv?utm_term=resumen+libro+el+pais+de+las+sombras+largasPDF link annotation
    • https://drones.princeton.edu/system/files/webform/dovekilubexuvizufak.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_off0000cd13.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD13 5424 bytes
SHA-256: 77a31607386aa4bf4d7ff7da5a9f77e92cd348e60964b795f7862ea4385d49c6
font_01_sfnt_off0000df6a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF6A 11648 bytes
SHA-256: 34d33f7837b9610f0785466a2cbe3f977b6da50de43fef55b5fc993be2e6eba8
font_02_sfnt_off000105a5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x105A5 16132 bytes
SHA-256: 895f66822cee8096b629ba52ebdbe333aa959cf625638ac8af8884b25f69792f