Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb1fbc141b828976…

MALICIOUS

PDF

81.2 KB Created: 2021-04-01 20:31:34 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-07
MD5: 54c30373e6bc84a90545583a7e3a5d50 SHA-1: 8cffe5daff87593af6c8d757989de46489f179a4 SHA-256: cb1fbc141b8289767c0a6d8edfef6046298fc318f1c96c657d7620ba9f1a2eb1
186 Risk Score

Malware Insights

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

This PDF file was identified as malicious by ClamAV and an ML classifier. It contains a large number of external links, many pointing to disposable hosting, suggesting a link farm designed to redirect users to potentially malicious content. The primary URL, https://jacksth.ru/wix?keyword=letters+of+note+pdf, indicates a lure related to 'letters of note PDF'. No scripts were extracted, but the PDF structure and numerous external links strongly suggest it's used for phishing or distributing further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 6

  • 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 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://jacksth.ru/wix?keyword=letters+of+note+pdf PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4366633/normal_60267c5abe947.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4368971/normal_600ad6f93e157.pdfIn PDF document text
    • http://podeves.xyz/rirovunebugiseej0.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4493888/normal_603781d776b92.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4366401/normal_601258db588d6.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4481408/normal_603937bf6db14.pdfIn PDF document text
    • https://darojavanobize.weebly.com/uploads/1/3/4/8/134889586/vorirexijifofuvinep.pdfIn PDF document text
    • http://dutov.org/tinuxazegn8el.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4502493/normal_600a43953f634.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4472484/normal_6030a75c5d16e.pdfIn PDF document text
    • http://bilkaita.space/782314730823t9ts.pdfIn PDF document text
    • https://lamamamim.weebly.com/uploads/1/3/1/6/131606140/46ee6.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4379034/normal_601df38f269f2.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4459320/normal_605ab4d5ec52f.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4448733/normal_5fcea8298276d.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4475734/normal_5ff1ee322d557.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4467285/normal_5ffcc817c7467.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://uploads.strikinglycdn.com/files/064dc545-9b4a-4030-a99c-b4c8fe21b1e7/76622463756.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/ca771ca0-7f45-4ebd-8462-1809bc53cad0/how_do_i_know_the_alternator_is_bad.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/e51352f3-ee4d-4b78-b27e-70bf8d3fd8e4/the_boy_in_the_striped_pyjamas_novel_activities.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/d387e41b-c61a-4444-83b6-40dce99f9e36/raymarine_c120_gps_antenna_installation.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f241.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF241 4476 bytes
SHA-256: a90afb458c6016a1d58789289944601a335f4a92d9c2d000edf97912c3de6585
font_01_sfnt_off0001017d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1017D 11268 bytes
SHA-256: 5871fc34ffe76f79c1f6b3cba641263ac3180c40e28889e991d99f757f26d0dd
font_02_sfnt_off000127d2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x127D2 4324 bytes
SHA-256: 9f355172d696dda274cac500966718f112ce76951f19577ac4888987ea6471b2