Malicious PDF — malware analysis report

Static analysis result for SHA-256 817385acc9cbd807…

MALICIOUS

PDF

40.8 KB Created: 2020-11-05 03:55:17 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-14
MD5: 05a31913440ffbe03a0a303a53d31d26 SHA-1: e6211c37e9d789e336142f5e6bc40d63b9645a05 SHA-256: 817385acc9cbd807adfa296a7b72e174f4fad2538dda4d3ad94dbb78cf358c4b
194 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF contains numerous links, many of which point to redirectors designed for SEO spam and phishing. The primary malicious link, 'https://cctraff.ru/123?keyword=kitchen+equivalents+worksheet+answers', is identified as a malicious redirector. The document body, though heavily obfuscated, contains text suggesting it is a 'worksheet answers' lure, aligning with a phishing or scam attempt. The ML classifier also strongly indicated maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 5

  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • Image lure linking to an SEO redirector (free-download phishing) high PDF_SEO_UTM_REDIRECTOR_LINK
    PDF embeds an image with little or no body text and a clickable link to a multi-word utm_term / FeedBurner-proxied SEO redirector — the 'free ebook / solution-manual / document download' phishing family that ranks for natural-language search queries and routes the user into a payload/redirect chain. The PDF carries no exploit; the risk is the linked destination. Flagged structurally (image lure + SEO redirector) so it does not depend on a ClamAV/ML signature, and regardless of how many filler text pages the lure carries.
  • 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://cctraff.ru/123?keyword=kitchen+equivalents+worksheet+answers In PDF document text
    • https://cdn-cms.f-static.net/uploads/4365655/normal_5f8d021ee8ad5.pdfIn PDF document text
    • https://tumixivig.weebly.com/uploads/1/3/1/6/131636813/pelorewajabisanelu.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4421627/normal_5fa12eb4dc86c.pdfIn PDF document text
    • https://duxixujojive.weebly.com/uploads/1/3/0/7/130739103/2379673.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4406223/normal_5fa2daa256700.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4368218/normal_5f89155128ed2.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/guwutivupudutu/top_alt_right_websites.pdfIn PDF document text
    • https://s3.amazonaws.com/baxegezivumi/still_star_crossed_on_dvd.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/42bee3af-fda6-49a6-bb52-b5561c65bd34/saxaziminuwatofixewupinef.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/dd04f7a9-9847-473c-81d6-753c04afbacc/a_pocket_style_manual_5th_edition.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0500/5911/6712/files/college_algebra_study_guide_with_answers.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/34fbff1d-ca3d-4dc1-86b9-4ee9adbb76d7/97412451222.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/1c3134e4-e083-403e-afba-f84a6bb88708/jarajexoni.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_off000061e1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x61E1 5200 bytes
SHA-256: 49124f0fff3061d7b9ac43fcc85d4d8227b250f52babc475160f31d99a0db260
font_01_sfnt_off000073a4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x73A4 10352 bytes
SHA-256: 37ede02f5697f0af99e90147b80caf03b3dd90f495f21819005a8c9ce3473283

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