Malicious PDF — malware analysis report

Static analysis result for SHA-256 5fc3d3b7d86d40cd…

MALICIOUS

PDF

43.9 KB Created: 2020-09-30 06:35:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-22
MD5: 7deedb5e829c6588b4285a809820626e SHA-1: 605f5c31e8941f2392cdead4eb36a3d8e656a4cb SHA-256: 5fc3d3b7d86d40cdd4818e39c2290aa83b66898719b45f50c41b5f59de6b23b3
184 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a large number of embedded links, many pointing to disposable hosting, and one critical link to known malicious redirector infrastructure. The document body, though malformed, contains text suggesting it is a "medical fitness certificate format pdf download", which is likely a lure to encourage users to click the malicious links. The ML classifier 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.
  • 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/strik?keyword=medical+fitness+certificate+format+pdf+download In PDF document text
    • http://files.whatisforhomework.com/uploads/1/3/0/7/130776025/polisudi-lerena.pdfIn PDF document text
    • http://files.emmauswellbeingmatters.com/uploads/1/3/2/6/132681971/xorefu.pdfIn PDF document text
    • http://files.clearhrsolutionsd.com/uploads/1/3/1/3/131398250/rifet-zabaza-saretemufiwigo-gexegukux.pdfIn PDF document text
    • http://files.naonsandiego.com/uploads/1/3/0/7/130775866/kutimurewo-soxukata.pdfIn PDF document text
    • http://julatila.youngexpression.com/uploads/1/3/0/8/130874021/lulugusog_jafuzobaroxe_wafozigevoj.pdfIn PDF document text
    • http://sogux.raynecreative.org/uploads/1/3/0/7/130776089/sajadopa-pisirozu-wupebazowu.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://cdn.shopify.com/s/files/1/0431/5276/9192/files/46652345389.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0434/1753/4629/files/logo_quiz_level_21_answers_with_pictures.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0430/6717/9165/files/bajizebilolujul.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0432/5310/4790/files/microsoft_employee_benefits.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/001ee0c6-4349-4771-9523-1f3799970334/21959859052.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/adfc62d2-8a78-43ce-ac27-ac2b5f1ce735/zopunovemegopobezujorek.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_off00006c42.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x6C42 5400 bytes
SHA-256: 67b73f2d6cc9ba9c9effe9469f7f746e035179b20ef66f3b7db9566822c80db2
font_01_sfnt_off00007ea5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x7EA5 10540 bytes
SHA-256: aa3f9c4ff76510e2f68fd46794186b05aeb73ad02f6a122cd73095d25121a35f

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