Malicious PDF — malware analysis report

Static analysis result for SHA-256 21c1ee1dc34a4103…

MALICIOUS

PDF

94.0 KB Created: 2021-02-17 20:40:51 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-20
MD5: 52d92648942063b53fa53a5773f966c7 SHA-1: a1f985d8eee8af53601758568042b8e068f887e4 SHA-256: 21c1ee1dc34a41031d8265422485ce348bac017f72272f5737538ecb2bf4ab93
244 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript T1203 Exploitation for Client Execution

The PDF contains a large number of external links, many pointing to disposable hosting, and one critical link to a known malicious redirector. This indicates a likely SEO poisoning or phishing campaign designed to drive traffic to malicious sites. The ML classifier and ClamAV detection strongly support the malicious verdict.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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
  • 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 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.
  • 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/wix?keyword=samsung+steam+vrt+washer+manual In PDF document text
    • https://cdn-cms.f-static.net/uploads/4480889/normal_5fd11a25cfdcb.pdfIn PDF document text
    • https://cdn.sqhk.co/kenipafitu/evjjFJy/vafiwovutole.pdfIn PDF document text
    • https://fukuperuka.weebly.com/uploads/1/3/4/8/134883813/9400632.pdfIn PDF document text
    • https://cdn.sqhk.co/xuwolupenilu/1DjcA5U/45265377295.pdfIn PDF document text
    • https://nolizusumebixaz.weebly.com/uploads/1/3/1/4/131438071/kuvumux.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4385204/normal_60200367deb5d.pdfIn PDF document text
    • https://cdn.sqhk.co/jofutagi/wohdhgX/7_wonders_of_the_world_2019_list.pdfIn PDF document text
    • https://cdn.sqhk.co/sajatanugeg/fhhgejd/simox.pdfIn PDF document text
    • https://cdn.sqhk.co/legusovej/bhbhEgd/skyscraper_roller_coaster_construction.pdfIn PDF document text
    • http://tovarajuxelogag.iblogger.org/59981333451.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4481286/normal_5ff40f8e8d708.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/fosagoba/apple_facetime_auf_android.pdfIn PDF document text
    • https://s3.amazonaws.com/godewumazek/how_are_you_feeling_today_answers.pdfIn PDF document text
    • http://segixiw.epizy.com/sidisona.pdfIn PDF document text
    • http://jujizulafob.rf.gd/suxipilivorate.pdfIn PDF document text
    • https://s3.amazonaws.com/viregujipowuru/pemuruvagimuwezu.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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00012d3e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12D3E 5352 bytes
SHA-256: da17ae2e28f0c39451c55398aa52b7b9cdd0288c4d6655d23cef3ca16b32b173
font_01_sfnt_off00013f5a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13F5A 13660 bytes
SHA-256: f20abe86b0e6ffa0ee65dcf6215a33df652ea1eda99e113e14c9f798076aa14d

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