Malicious PDF — malware analysis report

Static analysis result for SHA-256 7841c73b36fb01b9…

MALICIOUS

PDF

80.7 KB Created: 2021-04-09 22:47:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-20
MD5: 2a8f36786c0cafc43d54a2be09e71531 SHA-1: 6e8030c3a5f79b7a6d50d6d9d7029a87f0b99825 SHA-256: 7841c73b36fb01b9e3a14d15fcfd01baa629299c2f371ea17b846ed8efa782b8
186 Risk Score

Malware Insights

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

The PDF file contains a large number of external links, many hosted on disposable domains, suggesting a link farm or SEO manipulation tactic. The primary URL, 'https://gimoguvi.ru/strik?utm_term=how+can+i+learn+chinese+by+myself', is presented as a lure. ClamAV and ML classifiers strongly indicate maliciousness, consistent with phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://gimoguvi.ru/strik?utm_term=how+can+i+learn+chinese+by+myself PDF link annotation
    • https://static.s123-cdn-static.com/uploads/4443292/normal_5fccd1002c70c.pdfIn PDF document text
    • https://kilewesiviteki.weebly.com/uploads/1/3/1/1/131163613/gakugodepaxeb.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4453335/normal_606bd64086e9b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4393911/normal_605245278ff94.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4499653/normal_604aed1eca8d3.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4447253/normal_600130342f122.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4455894/normal_6054787e1c077.pdfIn PDF document text
    • https://cdn.sqhk.co/zutomina/ejiTiGR/84184504923.pdfIn PDF document text
    • https://wifadesar.weebly.com/uploads/1/3/5/3/135345928/9613258.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4486193/normal_60653cb03d8c4.pdfIn PDF document text
    • https://munopufunorari.weebly.com/uploads/1/3/4/8/134881547/ad8b2778343098.pdfIn PDF document text
    • https://cdn.sqhk.co/ruxuvedije/o10ighf/cake_balls_recipe_with_cream_cheese.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4380213/normal_6000896091173.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/timeziso/voxavix.pdfIn PDF document text
    • https://3a00e800-a8eb-44ae-aafc-ae9aecab8e06.filesusr.com/ugd/1715bf_bed0b287601f4d0d83cc9d2205d081ed.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/mukutud/what_are_the_3_types_of_intermolecular_forces_and_what_are_the_differences_between_them.pdfIn PDF document text
    • https://e79dab91-b8ca-4f03-a7cf-74564eaa1d8a.filesusr.com/ugd/009cd4_85b214515cb84fdaa238871b5e0c4829.pdf?index=trueIn PDF document text
    • https://d5cf7a15-73c9-49c9-ad57-d4f0303abb0c.filesusr.com/ugd/0d002d_d1eeb47a65b542fba1eb52a182fac41e.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/wetevali/netflix_series_en_macbook.pdfIn PDF document text
    • https://s3.amazonaws.com/xeruxaxer/candy_crush_soda_saga_hack_android.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_off0000eda4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEDA4 3720 bytes
SHA-256: f65b13e2922e7618a62dcbebfa53a1c398851790a9e5aef4ecd2e79a62a71b37
font_01_sfnt_off0000fad6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFAD6 5416 bytes
SHA-256: d3e13797fdd730ad0ca800a19b3584e8baa64426955b82f26431cc236e29d1fe
font_02_sfnt_off00010d2d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D2D 11116 bytes
SHA-256: 0b775b716e0920308f3c856ca5e0fa9efafa7f720276087f51a04e03c14555a2