Malicious PDF — malware analysis report

Static analysis result for SHA-256 a328be0dd550a45c…

MALICIOUS

PDF

79.0 KB Created: 2021-04-03 21:35:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-23
MD5: 21218c88601d94d41a3f4920bff5a483 SHA-1: a4940c958290561c5aa2d3b7aee72110db8d1470 SHA-256: a328be0dd550a45c65a18c40a1c06ee3f2d27c2221abd2d938c6c2c307458f5f
126 Risk Score

Malware Insights

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

The sample is a PDF file flagged by multiple heuristics and ML classifiers as malicious, specifically identified as a phishing trojan by ClamAV. It contains numerous embedded URLs, two of which are highlighted by heuristics as potentially part of a link farm on disposable hosting. The document body, though heavily obfuscated, suggests a lure related to 'Absolutismo em portugal pdf'. The presence of external URIs indicates an attempt to redirect the user to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://leonvi.ru/award?keyword=absolutismo+em+portugal+pdf PDF link annotation
    • http://albatros-trans.ru/54559508914rcikj.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4492897/normal_5fd08b2c7f259.pdfIn PDF document text
    • http://form-copyrightservices.com/37762314359tic5u.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4492580/normal_604b3f384fb39.pdfIn PDF document text
    • http://olx-delivery.cc/16731175486od2v8.pdfIn PDF document text
    • http://helpcreditscore.info/rikki_tikki_tavi_story_book_reviewh8csb.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4416932/normal_60105b7cdd720.pdfIn PDF document text
    • http://lnstagaram-verifiedbadges-from.com/how_bout_a_dance_sheet_musickfxt4.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/a209ca6f-7095-40ff-a55c-7af2941cc71e/when_will_nail_shops_reopen_in_california.pdfIn PDF document text
    • https://3c86e5df-9a55-47dd-9d5b-c207b25ec6cd.filesusr.com/ugd/72bf36_7578bad7092f40239c6f62b63eaa7ace.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/0ed7ddae-02ef-4b28-896d-735a7f4b62d8/poreviketesinetoreguzu.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/cc918820-c795-41d9-96a9-d31e9f4a2e92/zujigaxepawijelofigit.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_off0000f36e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF36E 5492 bytes
SHA-256: 4941d658850eb0d0dafbb3a82ce502655ccf1c2d8bbd56a244f9bc6af673712c
font_01_sfnt_off000105fe.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x105FE 12592 bytes
SHA-256: 58892b529f5ac953f1f342a9558ee01e4aa8e895aa0f78de3be50f6342f62fa9

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