Malicious PDF — malware analysis report

Static analysis result for SHA-256 379425d41b8f4118…

MALICIOUS

PDF

77.7 KB Created: 2021-04-13 11:28:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: adee1a4f1870742cad1bfb53ae8a4ac6 SHA-1: badae1c7d0dbf2e8e21b58f0eac293272ef0f1c8 SHA-256: 379425d41b8f41186a7d1d12ecef3b88e1a5d1c360ce4f287a6cb5249c167c8d
186 Risk Score

Malware Insights

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

This PDF file was flagged as malicious by both ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains a large number of external links, many pointing to disposable hosting, suggesting a link farm used for SEO manipulation or to redirect users to malicious sites. The primary malicious URL identified is https://kuzutuzo.ru/strik. While no scripts were directly extracted, the PDF structure and the presence of embedded URLs suggest it is designed to redirect users to potentially harmful content.

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://kuzutuzo.ru/strik?utm_term=macbeth+movie+2010+vs+play PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4485299/normal_6052f831e0d47.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4447658/normal_6034c8c78ff2f.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4393628/normal_600afe4687476.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4412588/normal_5fdd6ca37e100.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4382952/normal_605b1124029b3.pdfIn PDF document text
    • https://cdn.sqhk.co/zitajazasu/plehbm1/20267068095.pdfIn PDF document text
    • https://cdn.sqhk.co/nuxoporerom/xhgtich/picture_ideas_for_1_month_old_baby.pdfIn PDF document text
    • https://cdn.sqhk.co/febapaji/7EhjNHh/thumbelina_full_movie_1994_hd.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4479474/normal_60220b532a189.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4489409/normal_604d8c8849924.pdfIn PDF document text
    • https://cdn.sqhk.co/wuzevunoxina/jiOhfZ1/joviduf.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4380859/normal_6047de1c505b0.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/a7cae53a-4c2e-4db9-b530-8c799658b24f/primary_one_mathematics_questions.pdfIn PDF document text
    • https://4a31e3f8-49e3-4331-b1a9-c0bb7a6b9dbc.filesusr.com/ugd/599f1c_085e2c76f28a4667a4c113eaa16d5a1b.pdf?index=trueIn PDF document text
    • https://03df18d0-0a94-4077-8b44-1f3cf8b7c870.filesusr.com/ugd/23a6c3_7613c5bddbc742d9ab9b9cdf82edf772.pdf?index=trueIn PDF document text
    • https://6f4861c6-cdf0-4a5f-ba2d-f9c5e5bfbee6.filesusr.com/ugd/77941b_387998c6f75d44f38b786fc720f72446.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/982e898b-38fd-4f1f-824e-ec41b517b5aa/what_is_person_centered_therapy_used_for.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/cec0f6a1-9b3c-401a-a360-10a371151ce9/93183093990.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/f86f6ffd-8963-4fab-8603-58ac8338eb8b/lopupafovuzo.pdfIn PDF document text
    • https://4590046d-f0a9-4171-b8a0-56ff8c1fe63c.filesusr.com/ugd/0bfb20_b3cc89c2aa19440eb395a76d102ddeee.pdf?index=trueIn PDF document text
    • https://a540aa65-2eb1-4ac3-86d0-bf6a54daac96.filesusr.com/ugd/2d797c_8e30fac517af4dbe98d8ec1f70f221e6.pdf?index=trueIn PDF document text
    • https://67536400-2f23-40e2-9d3a-36ae3f4dfb8c.filesusr.com/ugd/5312ea_7b18ad0c67ff4233a7163abd4cee3d94.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_off0000ef94.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF94 5708 bytes
SHA-256: 8b9700bc3b9379d21dfe430e898ae807a66b9008a5be0fc000999817d5943af5
font_01_sfnt_off000102f9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x102F9 11424 bytes
SHA-256: fcd405afb53a890c4998228956f9ec110ed2b2311c0840f6d976109a8d69c9f3