Malicious PDF — malware analysis report

Static analysis result for SHA-256 c671c072803ba5d2…

MALICIOUS

PDF

76.8 KB Created: 2021-03-15 01:58:45 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 6a6917d2fe8a7158d73acd9476f08ad0 SHA-1: 7a64a370eb244fa2efd937c99de8dcb170d34111 SHA-256: c671c072803ba5d23c2eb450d52fc96b9387d4344ac250fb79c5a07b0e31f596
186 Risk Score

Malware Insights

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

This PDF document contains a large number of external links, many of which are hosted on disposable domains, suggesting a link farm designed to distribute malware or phish users. The primary malicious URL identified is vilenefex.ru, which is likely used to serve a second-stage payload. The ML classifier and ClamAV detection strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • 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-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://vilenefex.ru/wix?keyword=movie+fire+update+apk+download
    • https://cdn-cms.f-static.net/uploads/4366976/normal_6015e746b68f6.pdf
    • https://cdn.sqhk.co/rajexizeba/jhgdyew/8177779747.pdf
    • https://cdn.sqhk.co/xesagomi/jdmicje/browser_ringan_terbaik_android.pdf
    • https://static.s123-cdn-static.com/uploads/4465402/normal_5fefc5c97c1e8.pdf
    • https://cdn.sqhk.co/wejawujagi/gjjc6hf/kaiser_pharmacy_phone_number_california.pdf
    • http://xiguzot.22web.org/washington_state_department_of_health_licensing.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/0dad3701-28d4-4a18-bad1-31e83d0646e0/what_is_the_cash_flow_equation.pdf
    • http://makuwuwamev.rf.gd/pibobox.pdf
    • https://147762ec-90f0-4523-8579-43cb3cd17c82.filesusr.com/ugd/6c48b9_6fb59ce4049c4b5d91002c7ce46e0e20.pdf?index=true
    • https://332892e0-6a2b-40ad-946e-e7c92c61c867.filesusr.com/ugd/3e5d97_98f368d2f557451e97aa5d302085aac7.pdf?index=true
    • https://uploads.strikinglycdn.com/files/70d59918-8914-41f0-9c4d-f2c79ea7b350/asus_rt-ac68_firmware_update.pdf
    • https://bb55feb6-a0c4-48ae-8f72-aea2c45912f8.filesusr.com/ugd/b9801a_31f46cc78495465cb5a8c3722259e924.pdf?index=true
    • https://ede8a7a3-2377-4e09-926a-401222b31c25.filesusr.com/ugd/81c89d_a39f37925d37468cbf19893917600635.pdf?index=true
    • https://uploads.strikinglycdn.com/files/e8064555-fcac-43ba-9c62-4e9702589c31/71124474099.pdf
    • https://cad90261-f038-4e8a-b384-2e0e37e6cb8c.filesusr.com/ugd/4c4e45_67dcff2a84ad47489ae62af3585ad7cd.pdf?index=true
    • http://kitomalisufed.epizy.com/71508977404.pdf
    • http://patigol.rf.gd/the_wave_todd_strasser_full_book.pdf
    • https://2903667b-e544-4972-ac7f-e5855aaa9b37.filesusr.com/ugd/2cc660_d955569722094f1d9c9d2c0f5720abaa.pdf?index=true
    • http://sezigan.epizy.com/88033372476.pdf
    • https://ddf64d59-5240-4154-9987-17dfc28e22c7.filesusr.com/ugd/cec570_79ccb0db2a7e43c2b49f50670155c957.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_off0000ef65.bin
66a9c2e8ebee76b8365593748b47f9afea97cd3b5cb14a522b4f6786c157b3eb		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEF65 5076 bytes
font_01_sfnt_off000100e1.bin
f3b2ed71e7f6df4200d83ca4f1269a99500b4386268ab0a0a7a682535375d6cf		 pdf-font-stream PDF embedded font (sfnt) at offset 0x100E1 10948 bytes

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