Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c0f39cb29181fb5…

MALICIOUS

PDF

53.8 KB Created: 2020-10-04 15:58:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: 160a1c62bed491f5d0958c1608321a91 SHA-1: df37278613d3b0266c918fcfda119169dbc53740 SHA-256: 4c0f39cb29181fb57db6c04daeaaa92663da2633e1387214535c3c58c7e89fa8
184 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a large number of links to external PDFs hosted on disposable domains, indicating a link farm or SEO manipulation tactic. One URL, https://cctraff.ru/pify?keyword=houghton+mifflin+harcourt+science+grade+5+answer+key, is flagged as a malicious redirector. The ML classifier strongly identified this PDF as malicious, supporting the conclusion that it is used for malicious purposes, likely to distribute further malware or engage in SEO spam.

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.
  • 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.
  • 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/pify?keyword=houghton+mifflin+harcourt+science+grade+5+answer+key In PDF document text
    • http://pomova.kitchenettecuisine.com/uploads/1/3/1/8/131856005/627316.pdfIn PDF document text
    • http://files.raphaelvillage.org/uploads/1/3/1/8/131858592/tologenixobifenifi.pdfIn PDF document text
    • http://togerebe.cfarrantcoach.com/uploads/1/3/1/4/131407736/kuzakomenazamibop.pdfIn PDF document text
    • http://files.thepositiverail.com/uploads/1/3/1/4/131436956/takakopupekux.pdfIn PDF document text
    • http://files.brkbuilding.com/uploads/1/3/0/8/130873838/4072562.pdfIn PDF document text
    • http://files.msachristiansen.com/uploads/1/3/0/8/130874320/b902c2.pdfIn PDF document text
    • http://minufip.smoothguide-internetfundamentals.com/uploads/1/3/1/3/131382693/vipivunikano.pdfIn PDF document text
    • http://files.highballhijinks.com/uploads/1/3/1/3/131381044/vawimomebubije.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/2949d04f-c018-41f0-a44f-4d7ebd7a5ddb/99343221309.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/8171baab-7146-48f3-b985-36e622480da4/kasoravoserovivamu.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/39b78d63-374f-485a-864e-0d4b03c9c9fb/dibilutorepuzu.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/b8214e58-1633-4aaa-a124-a71c0e771d47/liwasapopakezobaxu.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0481/1433/5897/files/solving_linear_equations_worksheet_algebra_1.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0431/0243/7527/files/weight_of_gasoline.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0430/9083/7655/files/school_of_chaos_hack_android_oyun_club.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0438/2362/8450/files/bunigagabiso.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_off00008d98.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8D98 5780 bytes
SHA-256: 6a1f2ab591eb249dae092aeef91a4b0758337bea0eb6b914b50b9312c9828aff
font_01_sfnt_off0000a132.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xA132 12420 bytes
SHA-256: bc4e07095091b3658c594c2881653953122d053e526533780390ef35d9f0bfab

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