Malicious PDF — malware analysis report

Static analysis result for SHA-256 4efb18b4898409db…

MALICIOUS

PDF

77.2 KB Created: 2021-09-24 05:53:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 763ff08fc58eb92fbdfe6a2070f6feb5 SHA-1: 35ee1f57deae852f08141f58afdd91f3cf7e24d7 SHA-256: 4efb18b4898409dbd7a3caecdafba764fd9aca3c812430d12ce808ab9a984657
66 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains numerous embedded URLs, many of which point to disposable domains and are structured as link farms. One prominent URL, 'https://coretry.ru/uplcv?utm_term=installing+a+firestick', suggests a lure related to device installation, likely for phishing or malware delivery. The ML classifier strongly flagged this PDF as malicious, indicating a high probability of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

Heuristics 4

  • 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://coretry.ru/uplcv?utm_term=installing+a+firestick PDF link annotation
    • http://www.emploi.nat.tn/ckeditor/ckfinder/userfiles/files/56136624224.pdfIn PDF document text
    • http://silarperu.com/UserFiles/file/75506278259.pdfIn PDF document text
    • http://av72-reklama.ru/userfiles/file/1630879204494ad58006c47a30f51c.pdfIn PDF document text
    • http://facyt.com.ar/ckfinder/userfiles/files/gimugafa.pdfIn PDF document text
    • http://7sate.com/filespath/files/20210908152531.pdfIn PDF document text
    • http://hexindechem.com/upload/files/84775905987.pdfIn PDF document text
    • http://ndt-tl.ru/upload/file/tupimipo.pdfIn PDF document text
    • http://www.gabrielamaciel.net/images/content/file/66703142272.pdfIn PDF document text
    • https://tsydesign.com/userfiles/jws/files/40860611690.pdfIn PDF document text
    • https://soportedevida.mx/ckfinder/userfiles/files/71240139775.pdfIn PDF document text
    • http://claudiamelchior.it/images/file/fetupakepijeximofebivegu.pdfIn PDF document text
    • http://abnigakgdsg.friendship-match.com/upload/files/89801187552.pdfIn PDF document text
    • http://2446665a.ru/ckfinder/userfiles/files/wesorumixojojip.pdfIn PDF document text
    • http://www.phonefixcomo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614a07571c3a7---zizatuvogitawerawez.pdfIn PDF document text
    • http://sin-hua.org/userfiles/61355803448.pdfIn PDF document text
    • http://wittlich-luexem.de/userfiles/file/23961032353.pdfIn PDF document text
    • http://cungcapbaoduongcuanhatban.com/upload/files/10984682478.pdfIn PDF document text
    • https://minhvuongthuphap.com/upload/ck/files/6174390084.pdfIn PDF document text
    • http://www.darvidproperty.com/news/file/8384486151.pdfIn PDF document text
    • http://www.grupoaccs.net/ckfinder/userfiles/files/35429725072.pdfIn PDF document text
    • https://copyjokertw.aw6.tw/uploadfile/qu4_qu106_com/files/guporewotaretu.pdfIn PDF document text
    • https://adminico.nl/userfiles/file/64978097997.pdfIn PDF document text
    • https://ienter.bg/files/10706074183.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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c909.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC909 18208 bytes
SHA-256: 98fa45a56b8cd6d740fdbed973cf9022a9bde8971d099b64ef92b6b64fdff01b
font_01_sfnt_off0000f7f4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF7F4 10432 bytes
SHA-256: 80049587610db2f5f01f9ac19a94bdcbec381df8ec80108eb8ada7ddd676120d
font_02_sfnt_off00010fb8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10FB8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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