Malicious PDF — malware analysis report

Static analysis result for SHA-256 31b840885acc9e8f…

MALICIOUS

PDF

78.4 KB Created: 2021-03-10 10:56:54 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-18
MD5: c9a0e29f62a32e0b80699f52cd2592d5 SHA-1: 99fa86fa88561e078ba1471cfcf0f368d7575e6c SHA-256: 31b840885acc9e8f8a01a71b1c709ce97b107b76bccf207a66d7256a67c84bb3
186 Risk Score

Malware Insights

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

This PDF document was flagged as malicious by ClamAV and an ML classifier. The file embeds a large number of external links characteristic of an SEO link farm. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

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://jacksth.ru/strik?utm_term=precio+libro+azul+xtrail+2015 PDF link annotation
    • http://fitatuvepejozo.sportsontheweb.net/prefixes_and_suffixes_worksheets_for_grade_6.pdfIn PDF document text
    • http://pedrons.space/lapixagluku6.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4404750/normal_5fe696819f1f3.pdfIn PDF document text
    • https://gilemana.weebly.com/uploads/1/3/5/3/135319463/3462207.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4501775/normal_5feb398ba975d.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4375690/normal_603e7f1b7c1eb.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4472776/normal_5fcd0b0204624.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4375517/normal_5fe6484dcceab.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4470391/normal_5fd7dd91a95c4.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4421969/normal_6036d2bac19e4.pdfIn PDF document text
    • https://zedabobosarafon.weebly.com/uploads/1/3/0/8/130813357/df7c1de12e.pdfIn PDF document text
    • http://trastqort.online/waxoba7xgxs.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4443372/normal_602d3b821f9a3.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4369334/normal_6040697640ade.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4496204/normal_5feef9c91ffa9.pdfIn PDF document text
    • https://zameleto.weebly.com/uploads/1/3/4/0/134042643/1569338.pdfIn PDF document text
    • http://mebelrostov.ru/nautical_knots_speed3xpqj.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://nijarigu.onlinewebshop.net/51760563549.pdfIn PDF document text
    • https://27f1a270-5048-4778-87f0-574dfe85248a.filesusr.com/ugd/b7306e_2085f8d7c96b4f2880fa1356d1016150.pdf?index=trueIn PDF document text
    • http://subogerilazelo.atwebpages.com/use_windows_shortcuts_on_mac.pdfIn PDF document text
    • http://kilarosine.atwebpages.com/tekoxesinagosavabavizoloj.pdfIn PDF document text
    • https://f4ef19d8-372f-49db-bbb6-0f5e16bfa625.filesusr.com/ugd/070799_f7def55c40c94588b74b9bb7360e3638.pdf?index=trueIn PDF document text
    • https://737bf953-b780-43bc-8af0-312ed5328a40.filesusr.com/ugd/017c44_e7fc73469e4144faa6cea97355356a7f.pdf?index=trueIn PDF document text
    • https://41fe7446-7195-45c8-906d-de5e784989f9.filesusr.com/ugd/e02969_dc58659be6184625962509d9a4443846.pdf?index=trueIn PDF document text
    • https://b4095e1f-5e43-4c35-8b28-ff0c3185c247.filesusr.com/ugd/9cc3de_3003281ac790494c9f923880fdfc2c9e.pdf?index=trueIn PDF document text
    • http://jokosen.atwebpages.com/clayden_warren_organic_chemistry.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_off0000f08c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF08C 5324 bytes
SHA-256: 3d8d10d5477010fff345ffe5ac19eae131e557c1172467eaddbfd5d2f1a65e98
font_01_sfnt_off000102c8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x102C8 12216 bytes
SHA-256: fc2d037e969e260a2377cb4e1c727b4061a7c58becf1219427beccd0a9859784