Malicious PDF — malware analysis report

Static analysis result for SHA-256 7682a2e5fb10d6e9…

MALICIOUS

PDF

76.5 KB Created: 2021-04-15 10:32:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: d0462356d56f7cfa591153fb9b210d1f SHA-1: 749fb75decf31818d37212976ccb02b7cc964e94 SHA-256: 7682a2e5fb10d6e93f31f2c104b78c859e51e06730ae7e073e5974fa14f5f52f
156 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics, including ClamAV and an ML classifier, as malicious. It contains a large number of external links, many of which are to PDF files, suggesting a link farm or redirection mechanism. The primary malicious URL identified is https://dafemum.ru/strik. The presence of embedded JavaScript, though not explicitly detailed in the provided evidence, is a common method for exploiting PDF vulnerabilities or initiating redirects.

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/strik?utm_term=chemistry+chapter+8+section+2+review+answers
    • https://sufudoni.weebly.com/uploads/1/3/4/8/134853368/8609111.pdf
    • https://cdn-cms.f-static.net/uploads/4498893/normal_6064e536d2b31.pdf
    • https://refodalisa.weebly.com/uploads/1/3/4/4/134437853/4755049.pdf
    • https://static.s123-cdn-static.com/uploads/4501495/normal_5fcbc505a5583.pdf
    • http://xepewifub.mygamesonline.org/degaxijogexipaxagofonesek.pdf
    • https://cdn-cms.f-static.net/uploads/4464323/normal_606dd7a30150c.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://746420f6-3007-491b-ba72-fd43be5094e5.filesusr.com/ugd/277b62_a975ae0606d14390a41e9220b9a17a5c.pdf?index=true
    • https://8ed7b8cb-9bae-4def-ad9b-66b28cd11f91.filesusr.com/ugd/740d8c_1fd4530bf6ba42cd8be9ce1369416ea2.pdf?index=true
    • https://f421159b-d329-41e8-bc42-072bc93e4c50.filesusr.com/ugd/65d6f7_a2422dbbc25e4c7185ed6b7ead7f21b9.pdf?index=true
    • https://b56e6f12-3f4b-4b75-bc29-9585eb3fba71.filesusr.com/ugd/73f0dd_d2d8a8e4683f41f4bc1c79cc0d6c928b.pdf?index=true
    • https://a19d597f-2220-41b3-9459-688249e8a20b.filesusr.com/ugd/f19f53_781095dec50845cfac92e057a806d50f.pdf?index=true
    • http://pudugivifo.myartsonline.com/quechua_language.pdf
    • https://34570882-574e-4d25-8c0e-d8b9b6c2967f.filesusr.com/ugd/cb2bed_065c4767adaa4ca8911643c16034c5bc.pdf?index=true
    • https://ebbb41b5-b8b7-4bfc-9e1b-23e79ad93844.filesusr.com/ugd/5eba67_5a118c0affa644bebdf347dc3003d098.pdf?index=true
    • https://332892e0-6a2b-40ad-946e-e7c92c61c867.filesusr.com/ugd/3e5d97_80605d96e2064ccc930c0a658ca7db5a.pdf?index=true
    • https://9b321a86-0615-40a7-b684-6dced782f4cc.filesusr.com/ugd/e3cae3_0cd496805ba84b038b5490332d942d1a.pdf?index=true
    • https://12350a4d-732a-4148-85a7-4fa27f2a77ec.filesusr.com/ugd/17beed_29f82881cfc74baa88d432929ffef485.pdf?index=true
    • 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_off0000ebfb.bin
9e9a76f37ea7d06ddfaf37ce3029eeb526ecb3a285d5f610caaba45f88670fe5		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEBFB 5624 bytes
font_01_sfnt_off0000ff08.bin
524e67fd7b73fd7e1c297a0325b46663237eb63cf66c1fd0c1bfbb8066a87393		 pdf-font-stream PDF embedded font (sfnt) at offset 0xFF08 10952 bytes

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