Malicious PDF — malware analysis report

Static analysis result for SHA-256 d8553629b71379d6…

MALICIOUS

PDF

72.8 KB Created: 2021-09-25 02:14:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 90aab014a0b5b67d834d674a043e1ef6 SHA-1: 0962e063814973fd5ceb8331a0a3b28cfa09a216 SHA-256: d8553629b71379d6ab73e10c5090a3c97e10c984497c2f49a9637ffbb8d6d222
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, containing numerous links to disposable domains, with one prominent URL pointing to a suspicious domain. The document body is heavily obfuscated, preventing a clear understanding of its specific lure, but the overall structure and heuristic firings strongly suggest a malicious intent to redirect users to harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

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://sanvexe.vn/webroot/img/files/gowikaseposesukikegule.pdf In PDF document text
    • http://mocphatreal.com/assets/images/ckfinder/files/66026048254.pdfIn PDF document text
    • http://nwatchonline.info/userfiles/file/mipirubokefijevavujavamuk.pdfIn PDF document text
    • https://pensiuneavalentina.ro/app/webroot/file/xusulevawudijobegazowofik.pdfIn PDF document text
    • http://marta-galan.com/files/varios/file/67562700239.pdfIn PDF document text
    • http://le-lemniscus-incandescent.fr/ckeditor/upload/files/zugumarepunemanupopemipoj.pdfIn PDF document text
    • https://tranhtreo.com/images/ckeditor/files/14150073809.pdfIn PDF document text
    • http://traktor-tv.de/sites/default/files/file/82751853948.pdfIn PDF document text
    • https://www.benkorner.nl/admin/library/ckfinder/userfiles/files/rijixajeduxex.pdfIn PDF document text
    • http://thoitranglani.com/upload/files/4602377041.pdfIn PDF document text
    • http://hairtransplantmangalore.com/uploaded_files/userfiles/files/81751579233.pdfIn PDF document text
    • https://atcotourismtravel.com/userfiles/file/96276235257.pdfIn PDF document text
    • http://naoshima-tours.com/images/blog/file/43747107337.pdfIn PDF document text
    • http://toeicspeaking.net/_UploadFile/Images/file/25138052189.pdfIn PDF document text
    • http://studiolorenzino.eu/userfiles/files/97122323960.pdfIn PDF document text
    • https://texigo.tw/upfile/files/2021/09/08/91222264516.pdfIn PDF document text
    • http://whatcanidoforyou.eu/publish/file/denusoj.pdfIn PDF document text
    • https://ln80.cn/filespath/files/20210910125656.pdfIn PDF document text
    • http://mixmarketing.vn/upload/fck/file/guxijanotabelatiginekik.pdfIn PDF document text
    • https://tucsonhomewindowtint.com/wp-content/plugins/super-forms/uploads/php/files/2233169e2a358d7fab6971d6fec7b586/juvebegelapadurazuzaz.pdfIn PDF document text
    • http://yao-cheng.com/uploadfiles/20210913083648.pdfIn PDF document text
    • http://zadonskiy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16131b97893443---96004291169.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=best+browser+for+battery+life+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_off0000b506.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB506 10740 bytes
SHA-256: 9811bf095cd11373c2e0cd6f5ada2e7c739824c862bacc8f461c5692d0a49581
font_01_sfnt_off0000cded.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCDED 18392 bytes
SHA-256: 685e2603f8381ff1b2c44a7bbe6044f5e33bc83f56ef217fe19bbd83f5e778ea
font_02_sfnt_off0000fd7b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD7B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1