Malicious PDF — malware analysis report

Static analysis result for SHA-256 8f8d8158fa80119a…

MALICIOUS

PDF

40.3 KB Created: 2020-10-10 10:02:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-22
MD5: 42d6d7a8eafbb94fe65aea0686262c03 SHA-1: 72f398983ef87d35530b3c8781b004ee09e3ad41 SHA-256: 8f8d8158fa80119a1a20d806663ef695a7a4a9161a9e9bfb9f12cc4c8a725381
184 Risk Score

Malware Insights

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

The PDF file contains a large number of embedded URLs, many of which point to disposable hosting and redirect to a known malicious domain. The document body, though heavily obfuscated, contains the URL 'https://cctraff.ru/strik?keyword=calendario+2019+escolar+2020+madrid', which is flagged as malicious. This indicates the document is likely a link farm designed to lure users to malicious infrastructure.

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=calendario+2019+escolar+2020+madrid In PDF document text
    • https://site-1037883.mozfiles.com/files/1037883/32774088261.pdfIn PDF document text
    • https://site-1039279.mozfiles.com/files/1039279/81489947490.pdfIn PDF document text
    • https://site-1044113.mozfiles.com/files/1044113/taritojibiv.pdfIn PDF document text
    • https://site-1037260.mozfiles.com/files/1037260/24546256430.pdfIn PDF document text
    • https://site-1037121.mozfiles.com/files/1037121/kukakepafa.pdfIn PDF document text
    • https://site-1036640.mozfiles.com/files/1036640/nufoxudir.pdfIn PDF document text
    • http://files.jackiecheuvront.com/uploads/1/3/1/4/131454172/b48c3e2b491c5f9.pdfIn PDF document text
    • http://files.katoutofbag.com/uploads/1/3/0/7/130776255/cfcc75473ae7690.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/f27223a5-9fe3-4c9f-93c0-10498cfc7688/wizijagifob.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/6178fad3-7ab2-402f-81bf-3210a1b8a608/vivofa.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/efbec2cc-86ed-424c-9e21-cf6bdb7ca896/17703751302.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/f6f41272-36ac-4525-ae92-163872ed9808/99894625461.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/1d9c6201-bc01-4e07-a153-feebe84f61b0/gejosarinaxobetixesivamo.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_off00005c8a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x5C8A 5472 bytes
SHA-256: 1a4f78d21d4fdb7ee6b7d04f416a0e4d761bde0fe7baeb6f3828e7b90d49c025
font_01_sfnt_off00006f0a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x6F0A 10896 bytes
SHA-256: 37bc836945252498ba246dea9495a0d2b1da81bec305f6172f8a8037b43cb383

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