Malicious PDF — malware analysis report

Static analysis result for SHA-256 684299a20315460f…

MALICIOUS

PDF

68.9 KB Created: 2021-03-26 09:55:22 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-23
MD5: 893f6f0ce7d917e1af73988027fd52bc SHA-1: aed71a9faab37d31541af3ae4e9a7278eccc1bc4 SHA-256: 684299a20315460fdcbd309c4707bf923f6f21c2bc7bc5781cedd7da1c045e0c
184 Risk Score

Malware Insights

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

The PDF contains embedded URLs pointing to known malicious redirector infrastructure, as indicated by the PDF_MALICIOUS_REDIRECTOR_LINK heuristic. The ML classifier and ClamAV also flagged this file as malicious, specifically as a phishing trojan. The document body, though heavily obfuscated, contains text related to 'American red cross bls instructor bridge test answers', suggesting a lure to trick users into clicking the malicious link.

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
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://crophysi.ru/strik?utm_term=american+red+cross+bls+instructor+bridge+test+answers In PDF document text
    • https://cdn-cms.f-static.net/uploads/4470226/normal_6029742fd80ab.pdfIn PDF document text
    • http://rozujed.sportsontheweb.net/nutup.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4375541/normal_605bc5e0b0e23.pdfIn PDF document text
    • http://lifeit.pro/rosemount_5300_series_reference_manualxamo7.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4416656/normal_6026785aa1c0f.pdfIn PDF document text
    • http://petersikdar.com/64644505673kusfv.pdfIn PDF document text
    • http://drilltech.info/remote_access_server_enable_windows_10m8cqn.pdfIn PDF document text
    • http://mavpa.fun/81920262806zs2op.pdfIn PDF document text
    • http://vadanunagirira.getenjoyment.net/enlace_covalente_polar_y_no_polar.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://77abcf6a-1f47-4233-a5f7-28832101be0a.filesusr.com/ugd/e29e5c_6481e744d43f42699a64869e7adf4ba8.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/zedilegol/xegiluz.pdfIn PDF document text
    • https://s3.amazonaws.com/goneduzum/4._4_biomes_answers.pdfIn PDF document text
    • https://76df98a8-3e94-4eee-a6f5-23e1de06049b.filesusr.com/ugd/54c74c_1d7d084809384e2ea3287711495513dd.pdf?index=trueIn PDF document text
    • https://0c82233a-88c4-4738-b239-c982c2329158.filesusr.com/ugd/7ab50f_c5472d033de4490a868d4ae211117343.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_off0000cda6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCDA6 5480 bytes
SHA-256: 718895f37137d1cc735fe3649b353e0481f8407f5ff00a661e2aa6bc432892b8
font_01_sfnt_off0000e03d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE03D 11384 bytes
SHA-256: 439896a85f19d25b02e9265542af0120d1380f0cf3da6eb73a44e3f1c049bb7e

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