Malicious PDF — malware analysis report

Static analysis result for SHA-256 a2cc50bfd346f87d…

MALICIOUS

PDF

37.4 KB Created: 2020-11-06 19:22:13 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-07
MD5: a2673d9d966d1a7c36e0d2c50366d832 SHA-1: 98c5a3d2b4d58c6e114fc8a486a5227aca19e7be SHA-256: a2cc50bfd346f87d4201422e6329a89e0743304358432d7e51e0bbde8d92f698
126 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many hosted on disposable domains, indicating a link farm or SEO spam campaign. The ML classifier strongly flagged this PDF as malicious. The embedded URLs, such as https://trafffe.ru/aws?keyword=human+genetics+practice+worksheet, are likely used to redirect users to malicious content or further stages of an attack.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 5

  • 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.
  • External URI info PDF_URI
    PDF contains an external URL action
  • 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://trafffe.ru/aws?keyword=human+genetics+practice+worksheet PDF link annotation
    • https://fijojonibiw.weebly.com/uploads/1/3/2/6/132681787/5648329.pdfIn PDF document text
    • https://biwugina.weebly.com/uploads/1/3/1/1/131163984/7411.pdfIn PDF document text
    • https://fodezamu.weebly.com/uploads/1/3/1/4/131407453/zuvekazabuz-topofelo-gupolekodojavo-ponabiloxe.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4382192/normal_5f98937ed6fd9.pdfIn PDF document text
    • https://bukusafirede.weebly.com/uploads/1/3/4/2/134266240/828d90a5.pdfIn PDF document text
    • https://xironudobavus.weebly.com/uploads/1/3/4/4/134461104/4619193.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/d41d0188-0bde-44a1-95cc-be78e57db3da/xokimigusasebefekud.pdfIn PDF document text
    • https://s3.amazonaws.com/pafiganovavi/red_cherry_peppers_plants.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/6888eed5-5879-46c0-bf10-0c89b0da29a8/34460017204.pdfIn PDF document text
    • https://s3.amazonaws.com/kewuxejikiwe/verenesiwixuj.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/905cc7f1-c541-421c-b6f9-3e5e398e04db/86770376637.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_off000053a7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x53A7 5432 bytes
SHA-256: 1d0dcb36d5f19cf58b2428e5c83a8222286c733079e32987cef81835474c8965
font_01_sfnt_off0000660a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x660A 10232 bytes
SHA-256: 83f3290151ac1a2f23c285387c16644562d84939c986241838de28ed42202279

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