Malicious PDF — malware analysis report

Static analysis result for SHA-256 81983acbdda9d626…

MALICIOUS

PDF

44.3 KB Created: 2020-10-01 16:45:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: dbfdedba37d91b7e37678a3d0308b0e9 SHA-1: 79ebf5b5ebacace191ae27cc60bca02968fc896e SHA-256: 81983acbdda9d626d6af5e8316325a78d4d1ecd32e33cbf175039aae3952fdf9
124 Risk Score

Malware Insights

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

The PDF contains embedded links that redirect to known malicious infrastructure, as indicated by the PDF_MALICIOUS_REDIRECTOR_LINK heuristic. The document body, though heavily obfuscated, contains text suggesting it is a lure for 'biology sample questions pdf'. The ML classifier strongly flagged this PDF as malicious. The primary IOC is the redirector URL used to funnel victims to further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • 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 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://gettraff.ru/strik?keyword=biology+sample+questions+pdf In PDF document text
    • http://files.terraheal.com/uploads/1/3/0/7/130775934/8199264.pdfIn PDF document text
    • http://files.butterflycat.org/uploads/1/3/1/8/131856949/xikafe.pdfIn PDF document text
    • http://files.kyheartwood.org/uploads/1/3/1/3/131398215/kirodukiv.pdfIn PDF document text
    • http://jexodebaf.outbuildingsok.com/uploads/1/3/2/7/132712593/8731263.pdfIn PDF document text
    • http://files.tarringtonswimteam.org/uploads/1/3/1/1/131163980/zodozumijefajaz.pdfIn PDF document text
    • http://files.mhecblacon.com/uploads/1/3/1/4/131437351/vasak.pdfIn PDF document text
    • http://rizamibu.yogibandits.com/uploads/1/3/1/4/131437889/mutafireremejon_laxafusubo_kokedokixafawud_mufoji.pdfIn PDF document text
    • http://rejake.macscanteen.com/uploads/1/3/0/7/130738568/d57309.pdfIn PDF document text
    • http://karedik.resilientpeople.ca/uploads/1/3/1/4/131454215/fafab.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/9a8b9767-fe5b-467e-b0de-d3ae4b9571a8/mogivekumoxubanom.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/66d0d54b-5b21-4b9b-bd65-5bf30ab0f3e0/sorarinipizowesa.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/34072ee0-d291-4afe-a626-faf2d16e8f19/tukujamatavojo.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/3ccf04ee-6f86-4636-9bbf-939402576727/fusikajen.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_off00006f46.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x6F46 5544 bytes
SHA-256: a258a4baa4bd84210fc14406e14a4d3f551e21b47a82d2a17d6b45577aeec469
font_01_sfnt_off00008226.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8226 10072 bytes
SHA-256: 0e31a408c8d18a77c4265059869932c65c74bdf9c2f127f65be3ae9bd71b8d63

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