Malicious PDF — malware analysis report

Static analysis result for SHA-256 51d4c835bd653ada…

MALICIOUS

PDF

75.9 KB Created: 2021-04-05 16:17:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: e91571da4ffa479fc893972efbaf0e1a SHA-1: c97c09656c26a16424329b190846c42089e32080 SHA-256: 51d4c835bd653ada593f6e63cb7d833ffe52672caac3f06b4270235ae3fde161
126 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The file is identified as malicious by ML classifiers and ClamAV, with heuristics indicating it's a link farm on disposable hosting. The document body, though heavily obfuscated, suggests a lure related to employment forms. The presence of numerous external URIs, including suspicious ones like 'kuzutuzo.ru', points towards a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://kuzutuzo.ru/award?keyword=employment+physical+form+pdf PDF link annotation
    • http://potuduwatolebu.mywebcommunity.org/basquetbol_historia.pdfIn PDF document text
    • http://nibewubixela.getenjoyment.net/menixijofoman.pdfIn PDF document text
    • http://lorubuxetorifa.medianewsonline.com/81150265961.pdfIn PDF document text
    • http://towufato.mywebcommunity.org/27913754368.pdfIn PDF document text
    • http://rafupofamurawaf.mygamesonline.org/fluke_t5-600_manual_espaol.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4391008/normal_5ff5a4ead333a.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4375076/normal_5ffa6f5fed3e3.pdfIn PDF document text
    • http://tijudozi.scienceontheweb.net/turikonimaminanane.pdfIn PDF document text
    • http://xijonofupawulo.mypressonline.com/99285132637.pdfIn PDF document text
    • http://zotikarida.medianewsonline.com/begipeximazunegunowisuban.pdfIn PDF document text
    • http://nojigopagapusu.mygamesonline.org/97508610581.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4498348/normal_6024bdb56079d.pdfIn PDF document text
    • http://xedeporib.medianewsonline.com/sopurikixulepidekagef.pdfIn PDF document text
    • http://pupapumibe.sportsontheweb.net/serusanotokupoka.pdfIn PDF document text
    • http://sakulog.sportsontheweb.net/fidupixivivomepuwisuk.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4383327/normal_6022d3fc634ef.pdfIn PDF document text
    • http://tulumiv.medianewsonline.com/kafizer.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/fewifuwu/spirit_airlines_fleet_information.pdfIn PDF document text
    • https://s3.amazonaws.com/zamemigojat/samsung_hw-j450_factory_reset.pdfIn PDF document text
    • https://s3.amazonaws.com/vasofirida/44655199914.pdfIn PDF document text
    • http://natukifuza.atwebpages.com/cdc_chlamydia_fact_sheet.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_off0000eb62.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB62 5452 bytes
SHA-256: 7b48d89dd0e9e1e2a75515b46fb551830ffaa5b295d272ce18eedaefd9b70d73
font_01_sfnt_off0000fdcb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFDCB 10772 bytes
SHA-256: 23789c490b7b10b9ff0b5817f0ab2502e19f0a7169b46a3bd0341721ea05a37a

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