Malicious PDF — malware analysis report

Static analysis result for SHA-256 61a8acde1691e169…

MALICIOUS

PDF

81.8 KB Created: 2021-09-14 13:45:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: bd55c195a7dadbba326bf6bc85d4ecac SHA-1: 48e5f93f4b3523720825b7fb1b96e28d21215257 SHA-256: 61a8acde1691e1697291981f595e64081035698160ed805fc328b7339a358c8c
126 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains a large number of external links, many pointing to disposable domains, suggesting a link farm designed to host or redirect to malicious payloads. The presence of numerous PDF_SEO_DISPOSABLE_LINK_FARM heuristics further supports this, indicating a tactic to obscure the true destination of the malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 http://yksskj.com/ckfinder/userfiles/files/devupanubunipe.pdf In PDF document text
    • http://tjsyjdq.com/v15/Upload/file/2021932115234139.pdfIn PDF document text
    • https://novahealthclinic.ca/userfiles/file/bekasonewolimasemed.pdfIn PDF document text
    • https://aquariumfargo.com/wp-content/plugins/super-forms/uploads/php/files/71b07889a56e6ae2aab0e088c4f0811b/gedovomobudazodezeseta.pdfIn PDF document text
    • http://www.astmalek.cz/obrazky/file/14235356764.pdfIn PDF document text
    • https://www.huaikrachaohospital.go.th/assets/global/lib/ckfinder/userfiles/files/10256804619.pdfIn PDF document text
    • http://studiopignotti.it/userfiles/files/52190561334.pdfIn PDF document text
    • https://bakwanudang.com/contents/files/fomukepexefi.pdfIn PDF document text
    • http://delve-cr.com/uploads/74297332828.pdfIn PDF document text
    • http://gramercygrand.ru/files/file/gexusezusurana.pdfIn PDF document text
    • http://thefarmatarapahoecounty.com/userimages/buvovaxedojefovupuv.pdfIn PDF document text
    • http://vasekurzy.cz/userfiles/file/fowujefepuje.pdfIn PDF document text
    • http://elektro-galerie-hamburg.de/userfiles/file/52625096787.pdfIn PDF document text
    • https://aldwalia.com/userfiles/files/85038622269.pdfIn PDF document text
    • https://butchercurnow.com/img/shop/contents/68722723699.pdfIn PDF document text
    • http://lumieye.com/userData/ebizro_board/file/10882830190.pdfIn PDF document text
    • https://massagetheory.ca/wp-content/plugins/super-forms/uploads/php/files/90f42473ff19469d84666adb446f0544/dujis.pdfIn PDF document text
    • https://epgeptech.hu/ckfinder/userfiles/files/busufilowusij.pdfIn PDF document text
    • https://www.newhorizonscrisiscenter.org/ckfinder/userfiles/files/vopadorajibobekitove.pdfIn PDF document text
    • https://mobisteelegypt.net/userfiles/file/kenefaxakedozibibewidolux.pdfIn PDF document text
    • http://jowinbio.com/upload/files/202109141753032788.pdfIn PDF document text
    • http://www.salpasafarit.fi/tiedostot/files/wivufovufijan.pdfIn PDF document text
    • http://mazraeir.com/images/upload/files/semisiginaperoxalez.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/PmAiG5ZyT-k/uplcv?utm_term=uncharted+4+obb+file+download+for+androidPDF link annotation
    • 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_off0000dcc3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDCC3 16900 bytes
SHA-256: 76e67d75b873bfd04a99967929adf4bee94f06abbcfd790f8d2eac4f946f0df0
font_01_sfnt_off000108a5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x108A5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000120bc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x120BC 10716 bytes
SHA-256: 3a404fde97f9fd6efa7864e8b81baa1d4d16247ce181541e81a7f8cbd2992b1d