Malicious PDF — malware analysis report

Static analysis result for SHA-256 bf3dab7a7936b087…

MALICIOUS

PDF

81.9 KB Created: 2021-04-01 01:14:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: d8b108f37e5d5f2ffc1e5ab95b3f142a SHA-1: 9ba99cb62541b184f03670b4de321d04c7c668ff SHA-256: bf3dab7a7936b08767158944b21c1719bbe5d670281da9900559ebbb53695a81
126 Risk Score

Malware Insights

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

The file is identified as malicious by multiple heuristics and a machine learning classifier, with ClamAV detecting it as Pdf.Phishing.Trojan. The presence of numerous external URIs, many hosted on disposable domains, strongly suggests a phishing or malware distribution attempt. The document body, though heavily obfuscated, contains references to 'wkhtmltopdf' and a date, indicating it was likely generated programmatically to appear as a benign document, such as worksheets, to lure victims to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9995

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 https://kuzutuzo.ru/aws?utm_term=perimeter+area+and+volume+worksheets+pdf+grade+6 PDF link annotation
    • http://zajapokel.22web.org/32733750357.pdfIn PDF document text
    • https://cdn.sqhk.co/pigajifaw/Yighfjj/sofizujuxizipu.pdfIn PDF document text
    • http://bigakeka.iblogger.org/11824306199.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4486221/normal_60365ce36f4dd.pdfIn PDF document text
    • https://cdn.sqhk.co/lidojuxuxiro/aiaiaI4/agl_energy_annual_report_2015.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4505771/normal_6000d37fc621c.pdfIn PDF document text
    • http://zopaxonurur.iblogger.org/66940095866.pdfIn PDF document text
    • http://marabape.iblogger.org/blasphemy_against_the_holy_spirit.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4481157/normal_5fd7001bc9b8e.pdfIn PDF document text
    • https://cdn.sqhk.co/xabiximakef/haifEih/tixominazi.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4472186/normal_604d8bbba5f66.pdfIn PDF document text
    • http://lopavatizurafe.iblogger.org/60618196112.pdfIn PDF document text
    • https://cdn.sqhk.co/nobutowug/cajhxIR/artificial_intelligence_a_modern_approach_third_edition_solutions.pdfIn PDF document text
    • https://cdn.sqhk.co/tuwagezo/duiejfB/lokadu.pdfIn PDF document text
    • http://mavurelaro.22web.org/60570923953.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/toguvaju/cuentos_chinos_andres_oppenheimer.pdfIn PDF document text
    • https://s3.amazonaws.com/fowonaxul/78259232092.pdfIn PDF document text
    • http://lexizilasajeso.rf.gd/badminton_world_federation.pdfIn PDF document text
    • http://tureverikatefe.epizy.com/jenis_bronkodilator.pdfIn PDF document text
    • http://kuwexugebukutim.rf.gd/33314995946.pdfIn PDF document text
    • https://s3.amazonaws.com/tafogusegabomu/28943405754.pdfIn PDF document text
    • https://s3.amazonaws.com/dadupawo/duwotolepazag.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_off0000e877.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE877 5828 bytes
SHA-256: d73ec7866e43c81cac445a8146901e9f6d0786196a0edaabcd1c3b722c0df08e
font_01_sfnt_off0000fc39.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC39 11264 bytes
SHA-256: 7668f41733ac78235008a2819825e40ccd32928647a0f2276c4733d65641451c
font_02_sfnt_off0001227e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1227E 16144 bytes
SHA-256: a0532d1212509dae036733b1fb6f303b0d7fd7a209d3928fdad713008da19d30