Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b55e009a7d20d10…

MALICIOUS

PDF

77.4 KB Created: 2021-03-30 05:06:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-23
MD5: e815b91fabe93f24645c7be38d4b76a8 SHA-1: cf244b6c808bbaec16b7303b92d89788b99a9f83 SHA-256: 4b55e009a7d20d10e830b392fd4cc1800b544bcf928f95c7620bb014250467a3
186 Risk Score

Malware Insights

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

This PDF file was identified as malicious by ClamAV and an ML classifier, indicating a high probability of malicious intent. It contains a large number of external links, suggesting it's part of a link farm designed to drive traffic to various websites, potentially for SEO manipulation or phishing. The document body is heavily obfuscated, but the presence of external URIs and the PDF_SEO_LINK_FARM heuristic strongly suggest the primary function is to redirect users to other sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • 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 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.
  • 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://druttle.ru/award?keyword=varicose+veins+management+pdf PDF link annotation
    • https://static.s123-cdn-static.com/uploads/4443814/normal_5fec870660b38.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4496165/normal_600bc81e35e46.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4490519/normal_5fcf4531e6360.pdfIn PDF document text
    • http://savupubib.22web.org/western_blotting_technique.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4446270/normal_5fe53e2e63044.pdfIn PDF document text
    • https://metonokosaza.weebly.com/uploads/1/3/2/6/132681587/19f00.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4457312/normal_5fcf99019f7ec.pdfIn PDF document text
    • https://buwumesuja.weebly.com/uploads/1/3/5/3/135303403/pamemeb.pdfIn PDF document text
    • https://fivitilanafime.weebly.com/uploads/1/3/5/3/135395402/6840958.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://aa0e52d0-3c12-4d86-bfd3-e3284f950a51.filesusr.com/ugd/eb1974_4038b082cedb4cc4bb739693cb031dcf.pdf?index=trueIn PDF document text
    • https://be1d055c-b83b-422e-9e68-1bf13cef350c.filesusr.com/ugd/5b1e3c_733efdba93c549f1871d051ee69bf259.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/9396abb1-64ff-4d86-b325-0f16698a483e/what_is_the_best_course_for_investment_banking.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/b40ac418-8dcd-40dc-b6ab-13748e46c068/richard_durrett_stochastic_calculus_a_practical_introduction.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/c77b3bbe-1fbb-492b-ba76-8d8fa1e55aea/bedtime_stories_filming_locations.pdfIn PDF document text
    • https://66f9c2bc-82a6-463d-9ccd-9c94d3d8805e.filesusr.com/ugd/b361c6_2b08e0444eae4611962d0ac5a2bd116c.pdf?index=trueIn PDF document text
    • http://risafajafefe.rf.gd/bing_app_windows_8.pdfIn PDF document text
    • https://a91873a8-1f5b-4151-915d-af39eb211f25.filesusr.com/ugd/3f80ec_f13e1ec00f9f45f989f2c4c9b32b2a39.pdf?index=trueIn PDF document text
    • https://d7e981a8-8c4a-445e-aef0-60d3d4911bd2.filesusr.com/ugd/65d69c_c6939abd41894b9c80084b0ffb55868a.pdf?index=trueIn PDF document text
    • https://746420f6-3007-491b-ba72-fd43be5094e5.filesusr.com/ugd/277b62_d8bc19b5204e438491190d9018fd6aab.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/4076afda-809e-4336-ba10-17019d698bba/95777557412.pdfIn PDF document text
    • https://9e77dbea-16d6-438e-9859-4a68c5388828.filesusr.com/ugd/3225da_46ad378d783d4faeb5e2e8bc5793df96.pdf?index=trueIn 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_off0000f1fa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1FA 5468 bytes
SHA-256: 46300e479634226b2e3446ea30dca5866715c2d38eb760a5a739e601f66a07eb
font_01_sfnt_off0001048b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1048B 10528 bytes
SHA-256: a47f992eaed541117e244d67a50559e95960f8a52d4a204c5d6f0376b7ff6dc4