Malicious PDF — malware analysis report

Static analysis result for SHA-256 81eadd37b2746919…

MALICIOUS

PDF

83.8 KB Created: 2021-03-27 19:24:16 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-24
MD5: 4de6ede7497167044b59c55d9e26530e SHA-1: 2845ff87923525834405bff2fe031355052f8bf9 SHA-256: 81eadd37b2746919724248bffb0136a631f016188af6bc434e52a5ef1a388732
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous external links, with a significant number pointing to disposable hosting, indicating a link farm or SEO manipulation tactic. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution via these links. The document body is heavily obfuscated and contains metadata suggesting it was generated by wkhtmltopdf, a tool often used to create PDFs from web content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://nipisod.ru/award?keyword=guia+de+medicina+ambulatorial+e+hospitalar+unifesp+pneumologia+pdf PDF link annotation
    • http://teren.fun/kepetavatitetilarexibepavk8ajn.pdfIn PDF document text
    • http://scoretdho.best/erythropoietin_anemia_guidelineskcgqi.pdfIn PDF document text
    • http://indital.fun/digital_marketing_plan_template_excel_free_downloadihwig.pdfIn PDF document text
    • http://apple-fruit.space/stihl_bg55_leaf_blower_reviews9w9ji.pdfIn PDF document text
    • http://brumbum3.xyz/mixed_present_tenses_exercises_intermediateurryu.pdfIn PDF document text
    • http://banki-internetowe.com/mitologia_griega_celta_y_romana_libro78vw4.pdfIn PDF document text
    • http://businesslinecenter.com/hire_plunge_saw_and_guide_rail4ob2h.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://dc6b22d1-fd3c-476a-b8f1-b0505981f591.filesusr.com/ugd/ab5adf_745a8e99f607430296cc9f2cae00f9ac.pdf?index=trueIn PDF document text
    • https://09235f31-469a-4613-94fc-36d04c1f642a.filesusr.com/ugd/8b6407_1fadec67309c4b2ab80e3628004c043e.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/8f9ef3b5-c934-4927-a077-6bd8ee6ff830/teboxazi.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/5c6eba3d-1681-438a-a798-41f963754122/puppet_show_big_fish_games_list.pdfIn PDF document text
    • https://4f640d82-8365-4c22-93d6-dbd3427c3fb0.filesusr.com/ugd/55e8b7_9c6264630719472bb6cb50847959fdc0.pdf?index=trueIn PDF document text
    • https://54957a25-093b-4cbd-a4f0-8eb5fea931f0.filesusr.com/ugd/8ba634_d9dfed38070146f4abef01ed2a3e1c98.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/a1a2be3b-b367-42d9-9853-9ca01fa6b21d/86574330455.pdfIn PDF document text
    • https://7e005a1c-fb68-43c1-af83-b854b6a2d282.filesusr.com/ugd/dcfb95_0cc9cc1be00b4c529d3b96d4c49c5734.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/4e96ca6d-1c6e-479a-a486-4dd93e58fcb6/malikikos.pdfIn PDF document text
    • https://13a7c488-548c-4b48-b567-d2b0b9a3e1de.filesusr.com/ugd/85d67f_b6b80c723e3d422cbbb2f7cbbdbac35f.pdf?index=trueIn PDF document text
    • https://1d942ef5-affb-47d8-8f99-70a3d187b733.filesusr.com/ugd/3283b0_1324190b547f4cb79ba2e1fc79ccae1f.pdf?index=trueIn PDF document text
    • https://b01ec662-dec5-4f54-b977-8708717d6054.filesusr.com/ugd/07e02c_8ae3dc9b4fb549da809d46ba724b326b.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_off00010332.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10332 5740 bytes
SHA-256: 14cde246f02353c882cafe128b75edc893501028bf2739a2b93308a39b49f438
font_01_sfnt_off0001168f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1168F 13612 bytes
SHA-256: 9cd66e546a5531a0584b79da4bb63bb9a38d15c997deb79ffcb2fff6872ff2e4