Malicious PDF — malware analysis report

Static analysis result for SHA-256 b5085fe9a20c740a…

MALICIOUS

PDF

80.9 KB Created: 2021-02-25 23:56:04 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-16
MD5: dfdba234d6994ed506d884d2b43313d1 SHA-1: df99f753996a1cb0a4ca5f7102b42d2744d10577 SHA-256: b5085fe9a20c740a7a6aa4dc0bb51651e8d40faa6c08bde64ff3e0f94a1759c7
126 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF file was flagged by multiple heuristics, including a critical ClamAV detection and an ML classifier indicating maliciousness. It contains a large number of embedded URLs, many pointing to disposable domains, suggesting a link farm designed to redirect users to malicious content. The document body is heavily obfuscated and contains metadata related to wkhtmltopdf, but the primary malicious activity appears to be the extensive use of external links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://druttle.ru/strik?utm_term=epson+wf+2630+printer+cable PDF link annotation
    • http://detonic-romania.website/computer_architecture_and_organization_notes_pptvv84j.pdfIn PDF document text
    • http://pazujiz.mygamesonline.org/lajix.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4468294/normal_601855e6166ce.pdfIn PDF document text
    • https://gemexufata.weebly.com/uploads/1/3/0/7/130739895/retikoba_norokobogegar.pdfIn PDF document text
    • https://cdn.sqhk.co/molodomo/gjifqie/2489043904.pdfIn PDF document text
    • https://cdn.sqhk.co/bapinero/c7gdijw/25748783883.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4366022/normal_6025430bcc17a.pdfIn PDF document text
    • http://testersairf.xyz/77596986723egr66.pdfIn PDF document text
    • https://kevosenebiv.weebly.com/uploads/1/3/1/8/131871602/2600120.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4382638/normal_6003c1e4efc8d.pdfIn PDF document text
    • http://nuloriwilorij.scienceontheweb.net/purisomedolepopatu.pdfIn PDF document text
    • https://cdn.sqhk.co/pananumujo/a62jbii/rise_of_the_tomb_raider_posters_soviet_installation.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4368999/normal_5fd02bd996c33.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4383314/normal_5fca5d3fa8011.pdfIn PDF document text
    • http://checkmycredit.info/8989791617140hfi.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://nufiwimuzobo.onlinewebshop.net/81240932658.pdfIn PDF document text
    • http://tefetuzuzip.myartsonline.com/john_deere_compact_tractors_near_me.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_off0000fe0b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE0B 5788 bytes
SHA-256: cf8492cf5437c047e7d07b9e81b40769600aea3d04cdca83d02db144d5a86cf0
font_01_sfnt_off000111e1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111E1 10700 bytes
SHA-256: 4f6c056963bb385b8fc071942b98b6a0fc2f2af63ab6ef4b0964841cdb38d9eb

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