Malicious PDF — malware analysis report

Static analysis result for SHA-256 86b6f0528ee9657c…

MALICIOUS

PDF

88.6 KB Created: 2021-04-01 06:47:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-25
MD5: 94a58fac668229a847a54a98c06f319c SHA-1: cf164f2f2b9f0cc3835c7682d108e42063e4a6ff SHA-256: 86b6f0528ee9657c697f8f8bb8ce83754d56e93e197f45d98ed07957fc99177b
194 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many pointing to disposable domains, suggesting a link farm or SEO manipulation tactic. ClamAV detected this as Pdf.Phishing.Trojan, and ML classifiers also flagged it as malicious. The document body, though heavily obfuscated, contains metadata indicating it was generated by wkhtmltopdf, and the primary external URL is a search result page.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 7

  • 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.
  • Urgency / deadline lure low SE_URGENCY_LURE
    Document contains urgency or deadline language ('account will be terminated', 'action required within 24 hours', etc.) — useful context, but low-signal without other findings
  • 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://botokaw.ru/award?keyword=ascaris+lumbricoides+life+cycle+pdf PDF link annotation
    • https://sozazajigosana.weebly.com/uploads/1/3/0/7/130739782/43d13fb75.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4404296/normal_6018ee1111f3b.pdfIn PDF document text
    • http://instas.site/chicken_pills_before_and_afterrxmxb.pdfIn PDF document text
    • https://redupasatoli.weebly.com/uploads/1/3/4/4/134446027/d93c6e02875.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4422180/normal_5fd97de46a1a7.pdfIn PDF document text
    • http://braco.ru/81818669536b1yvy.pdfIn PDF document text
    • https://luwujapi.weebly.com/uploads/1/3/4/7/134751522/1277224.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4469852/normal_60456948083eb.pdfIn PDF document text
    • https://jedumetunu.weebly.com/uploads/1/3/5/3/135388943/vivokudot.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/nitidadufetenu/nodorowogot.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4c3fbbee-f661-450c-a4db-7bde1f604264/how_to_start_drawing_with_pastels.pdfIn PDF document text
    • https://s3.amazonaws.com/dukexajuj/33603863373.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4ce2f495-97ec-41ac-99a7-3e3889150c46/11385257735.pdfIn PDF document text
    • https://s3.amazonaws.com/woxojuxafopuv/dazawadosolexezor.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/cc1b7b67-31b0-4a66-9abc-b5829feba2c3/52189913159.pdfIn PDF document text
    • https://s3.amazonaws.com/dovulavavo/68285453463.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/f17346d6-aefa-4f48-be72-b3ea9805edec/casio_fx-9750gii_software_download.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/b8ec6041-60d4-4c0e-b900-8f06504ab81f/76786520146.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/3e0473f5-322c-4c0f-910c-e439dcf1942e/what_is_sociology_as_a_subject.pdfIn PDF document text
    • https://s3.amazonaws.com/xupimaral/nadedowifegad.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_off00011c22.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C22 5532 bytes
SHA-256: 48ef24d8eef7bc8c80a8aff5852b6e9f4edba190ca5483d0201ad413e290666e
font_01_sfnt_off00012ee5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12EE5 10724 bytes
SHA-256: 3a626b194ff1772631315b312a795d4010ebd840dc72233e6318bf831d7e4b7d