Malicious PDF — malware analysis report

Static analysis result for SHA-256 8c4c3d5756231b3e…

MALICIOUS

PDF

80.3 KB Created: 2021-03-31 03:44:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: f7f85de04cd44ac9f976af9dec136031 SHA-1: c5399ad4dbfc1d97d063400001c1af2e35446f53 SHA-256: 8c4c3d5756231b3eb80e4fa62cf253a125b20ab7f7be2162c524da8877d278f1
126 Risk Score

Malware Insights

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

The PDF document contains multiple embedded URLs, with a primary focus on directing users to a link farm hosted on disposable domains. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a deliberate attempt to obscure the final destination, and the ML classifier and ClamAV detection strongly suggest malicious intent. The document body, though heavily obfuscated, appears to be a lure related to educational materials, likely to trick users into clicking the malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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://gimoguvi.ru/strik?utm_term=math+2+dilations+practice+worksheet+answers
    • https://cdn-cms.f-static.net/uploads/4378855/normal_5fe765ad92c6d.pdf
    • http://b0xberry.online/786486228656f72h.pdf
    • https://cdn.sqhk.co/fosulavale/fjjSrja/boutonniere_deformity_treatment_therapy.pdf
    • http://pixxel.life/175801965410woej.pdf
    • https://cdn-cms.f-static.net/uploads/4493600/normal_5fe8870a37ff9.pdf
    • https://cdn.sqhk.co/fafovewidom/ijhejbD/rumexibifufe.pdf
    • https://cdn.sqhk.co/vajirasavuz/iabhhjc/samsung_clp_310_manual.pdf
    • http://itravelgr.com/815613501996v0rq.pdf
    • http://lidzadva.xyz/bnmu_result_2018o92p4.pdf
    • https://cdn-cms.f-static.net/uploads/4418197/normal_605b6a3983136.pdf
    • https://cdn-cms.f-static.net/uploads/4415930/normal_60537fc4d9c12.pdf
    • https://cdn-cms.f-static.net/uploads/4423428/normal_601e48428592b.pdf
    • https://cdn-cms.f-static.net/uploads/4378390/normal_601bc34a3c386.pdf
    • https://static.s123-cdn-static.com/uploads/4382952/normal_5fe55911e3730.pdf
    • https://cdn.sqhk.co/furabafezuse/WiitijF/anime_slanted_eyes.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://ac614e2c-2e00-43e4-a80f-2c6bce9fb64b.filesusr.com/ugd/f103bb_275b1a68988e4241afdcca18eb2a8f6f.pdf?index=true
    • https://1794ee33-230d-455b-98b1-84d48067edce.filesusr.com/ugd/551769_24b9e704d4cc4f3d8ed2afd4b0c23c24.pdf?index=true
    • https://6c49ff76-e13b-46da-8354-2e633d56f736.filesusr.com/ugd/211c2d_8e7d36de22ac4427adc113d622d2231f.pdf?index=true
    • https://068ba8bc-08b0-4b68-8151-f3c59c7a5775.filesusr.com/ugd/5a4aad_887c6caa68af48d9b3e39e2bfb63ba1f.pdf?index=true
    • https://73099f28-10d5-4558-98a1-2f8dc61f1a2f.filesusr.com/ugd/f62eaa_1a38741036184209b825d8b0540ccc2b.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
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e6bd.bin
f6fe1bc909493d78e31fc169208e32893321b4131a77a8cb320558dbce5b0b74		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE6BD 5452 bytes
font_01_sfnt_off0000f966.bin
7ebaafb144baab0f91ca072326b5d78077be85db59efe633f4ec9d00743537c9		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF966 10840 bytes
font_02_sfnt_off00011ea4.bin
aabbb95e4258a1bccfe6759090a0a8b97a33e8154131110566ffb2eaa8fdb080		 pdf-font-stream PDF embedded font (sfnt) at offset 0x11EA4 16148 bytes

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