Malicious PDF — malware analysis report

Static analysis result for SHA-256 f3d0aeed9ae94164…

MALICIOUS

PDF

79.7 KB Created: 2021-05-12 10:12:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-23
MD5: 831fa90dc4640b0dc98032cd21c7158e SHA-1: e0dea485fd29ef098ff32c4478998b3ecc07e965 SHA-256: f3d0aeed9ae94164fc24e04139010eb15f7fdc8730d4863d703699cd3d5f36f1
96 Risk Score

Malware Insights

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

The PDF document contains a large number of external links, many of which are dynamically generated, suggesting a link farm or SEO spam tactic. One prominent URL, https://pelibifir.ru/strik, is directly embedded and likely leads to a malicious site. The ML classifier strongly flagged this PDF as malicious, indicating a high probability of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 4

  • 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.
  • 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://pelibifir.ru/strik?utm_term=software+testing+course+fees+and+duration PDF link annotation
    • https://static.s123-cdn-static.com/uploads/4495413/normal_5fceefef3d6ad.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4366335/normal_5fefb5afb11f0.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4412396/normal_5fcc6f2c48a38.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4370089/normal_6024f5376276d.pdfIn PDF document text
    • https://fajorisovobune.weebly.com/uploads/1/3/4/7/134752278/09d1a5fec8ba.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4501204/normal_6006b00b8e7d4.pdfIn PDF document text
    • https://vanewuzopawibo.weebly.com/uploads/1/3/0/8/130814706/b191e30921b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4451575/normal_603b932a081a5.pdfIn PDF document text
    • https://jukejifoka.weebly.com/uploads/1/3/5/3/135311866/2289ec29.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4446045/normal_5fc72a43d77be.pdfIn PDF document text
    • https://mamowoxu.weebly.com/uploads/1/3/4/2/134265364/7498869.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4502493/normal_60491a26a4afb.pdfIn PDF document text
    • https://zizusufake.weebly.com/uploads/1/3/4/6/134646877/poxalagek.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://fb7bf4c5-056f-4058-a7d1-073478569b53.filesusr.com/ugd/d90490_04e07f5cf35d4a6a9349e145679e2810.pdf?index=trueIn PDF document text
    • https://c7f0abc7-d23b-482d-bd16-0771495bb668.filesusr.com/ugd/bb13a2_b951fa264ba04b3d82424d8bc469e920.pdf?index=trueIn PDF document text
    • https://5fb42ee6-a9be-400a-98f2-f9d4b9f720c8.filesusr.com/ugd/1813b3_02f3689013c14b61a47700039fa4609b.pdf?index=trueIn PDF document text
    • https://e0eedba4-cf99-4c42-97f5-d3f9ae5832dd.filesusr.com/ugd/e36ea7_33b27fa6e01a4724ba14a08f5135589a.pdf?index=trueIn PDF document text
    • https://b9a4c3d6-4ccf-4d04-9b0f-c2e9c357e15d.filesusr.com/ugd/e5cbe5_705bed38eb1d438e9022b8f4de90aeb1.pdf?index=trueIn PDF document text
    • https://c3373aeb-ed74-4f2d-b631-fa679e0a3f6f.filesusr.com/ugd/cbe7f7_03a4937ceeec498f89b86f3d63c4b77c.pdf?index=trueIn PDF document text
    • https://d321836a-1bf8-47c4-b4d3-67fe1e7f0250.filesusr.com/ugd/33ab24_e91181ca81724aeda440e4e39a5f8aa7.pdf?index=trueIn 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_off0000f9aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9AA 5352 bytes
SHA-256: cc4d1f7b6815de5f70859a3d2b89798ee8b5313024bfb6ebf52ed0eabc52cbd3
font_01_sfnt_off00010c01.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C01 11064 bytes
SHA-256: f49bf6a89297ab601e8b6fb3c0c4fb19a960e18849e7ea1989da8537df034098

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