Malicious PDF — malware analysis report

Static analysis result for SHA-256 f503a03d91b6f1b9…

MALICIOUS

PDF

81.8 KB Created: 2021-05-29 12:15:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: ba4396df3e91b8d7a4304e56b372cdd2 SHA-1: 66fc57503ba86a0cf30c0b59ed7272df9d81e648 SHA-256: f503a03d91b6f1b9a20964dfa45aa1885efe32f3dde64cc3727467b4dda33cf7
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, identified by the PDF_SEO_LINK_FARM heuristic, suggesting it is part of a link farm. The ClamAV detection and ML classifier strongly indicate maliciousness, with the primary function appearing to be directing users to other potentially malicious or SEO-abused content. No scripts were extracted, but the PDF structure itself is used to host a large number of external URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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.
  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://dafemum.ru/123?utm_term=fiesta+americana+vacation+club+member+guide+2019
    • https://cdn-cms.f-static.net/uploads/4383445/normal_6061314cd8195.pdf
    • https://static.s123-cdn-static.com/uploads/4384655/normal_5ff76ece7c0dc.pdf
    • https://cdn-cms.f-static.net/uploads/4488323/normal_601e39b1e2cdc.pdf
    • https://vupikesuxal.weebly.com/uploads/1/3/4/3/134397623/652797.pdf
    • https://static.s123-cdn-static.com/uploads/4447280/normal_600047431ec16.pdf
    • https://cdn-cms.f-static.net/uploads/4454054/normal_6041f3618416d.pdf
    • https://static.s123-cdn-static.com/uploads/4417119/normal_5fc893cf52a0a.pdf
    • https://cdn-cms.f-static.net/uploads/4496580/normal_6053347f5a798.pdf
    • https://wuriwodek.weebly.com/uploads/1/3/4/6/134688082/6692381.pdf
    • https://static.s123-cdn-static.com/uploads/4444623/normal_5ff9d062c33d9.pdf
    • https://cdn-cms.f-static.net/uploads/4483335/normal_6019ca6601b4c.pdf
    • https://xibupofuku.weebly.com/uploads/1/3/5/3/135306475/dorubum.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/388ea2cf-aac0-423a-a5c7-16dfd64a0ab3/how_to_enter_sootopolis_gym.pdf
    • https://uploads.strikinglycdn.com/files/15703037-5434-4011-80e5-220c6bcae161/somurel.pdf
    • https://uploads.strikinglycdn.com/files/9fe8fc26-f494-4776-90b9-ca909271fdb2/how_to_start_a_letter_of_recommendation_for_someone.pdf
    • https://uploads.strikinglycdn.com/files/8d293996-10cf-4d5e-9529-c2d86a1bca23/resumen_del_libro_los_ojos_de_mi_princesa.pdf
    • https://uploads.strikinglycdn.com/files/b5a995e0-5eaa-433d-98d9-9ff36f950f53/cambridge_placement_test_for_adults.pdf
    • https://uploads.strikinglycdn.com/files/56189a8b-e410-45c6-8cec-bbe1152c4224/rival_18_quart_roaster_oven_directions.pdf
    • https://uploads.strikinglycdn.com/files/d907379e-f41b-4465-b1de-dcb3b7182353/pifejujatuxilegubis.pdf
    • https://uploads.strikinglycdn.com/files/199bc788-7a3a-4643-9ba2-6b4cbf4f9481/dogar_publishers_ppsc_books_free_download.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0001004d.bin
9631d7ab130931a185249cdc075a5e9b71a45b746a0ba0363fa2a4cbee4a765a
pdf-font-stream PDF embedded font (sfnt) at offset 0x1004D 5896 bytes
font_01_sfnt_off00011449.bin
a63fff933b585de8e3035a5b7f6cdff17c92f4eef81fb14a90988845be543042
pdf-font-stream PDF embedded font (sfnt) at offset 0x11449 10908 bytes