Malicious PDF — malware analysis report

Static analysis result for SHA-256 31b41a953c853a4c…

MALICIOUS

PDF

79.9 KB Created: 2021-09-17 18:04:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 6a181b0943626f4f676f1bc453325664 SHA-1: 70f98186107f10ead90b53bfea1e3f2efd74ab87 SHA-256: 31b41a953c853a4cdf245770a2d5c4ebd8f841913fe8100399ea2ea17ef8f98c
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and numerous external URIs, many of which are hosted on disposable domains, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or distributing further malware. The presence of embedded JavaScript points to T1059.007, and the nature of the file suggests it was likely delivered as a Spearphishing Attachment (T1566.001).

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://huntic.ru/uplcv?utm_term=rpc+server+is+unavailable+android PDF link annotation
    • http://lsneotek.com/ckupload/files/76257177963.pdfIn PDF document text
    • http://cn-daomeng.com/upload/userfiles/files/ab8ab7366e2ac3249aec667a9976072e.pdfIn PDF document text
    • http://richmore.kr/uploadfile/fckeditor/file/60191653097.pdfIn PDF document text
    • http://visit-pune.com/userfiles/file/fimugozawivabivagadosa.pdfIn PDF document text
    • http://cdkuys.handysociality.com/upload/files/jiwaxodobowivetulupape.pdfIn PDF document text
    • http://wwm-quanta.com/upload/files/rozemodopi.pdfIn PDF document text
    • http://hzzxtl.com/UploadFile/file/20210911082718241.pdfIn PDF document text
    • http://tv-kitchen.ru/files/files/31171318627.pdfIn PDF document text
    • http://hyundaihungthinh.com/uploads/images/files/20480541525.pdfIn PDF document text
    • http://defhjdrjioo.friend-match.com/upload/files/26622978501.pdfIn PDF document text
    • http://bfttacg.marketsearching.com/upload/files/rejusadexutowo.pdfIn PDF document text
    • https://expungemyrecordnj.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c1478be5bd---65748561288.pdfIn PDF document text
    • https://www.keystonecare.co.uk/wp-content/plugins/super-forms/uploads/php/files/5cf73d1c9475a7d3a52d8ebbac7f5e30/95800341678.pdfIn PDF document text
    • http://4chan.ro/UserFiles/file/20126673869.pdfIn PDF document text
    • https://univerosg.com/ckfinder/userfiles/files/gozadaxuziboviwuvidex.pdfIn PDF document text
    • https://www.santaterezinha.com.br/js/ckfinder/userfiles/files/64273986551.pdfIn PDF document text
    • https://mehreganimaging.ir/images/upload/files/95685445092.pdfIn PDF document text
    • https://am-system.eu/ckfinder/userfiles/files/tojilezoj.pdfIn PDF document text
    • https://autosaloncenter.com/uploads/files/29731359002.pdfIn PDF document text
    • http://abnig.friendship-match.com/upload/files/zetezumawularaperakelaweg.pdfIn PDF document text
    • http://guojingmall.com/userfiles/file///87087142710.pdfIn PDF document text
    • https://rhodium.vn/uploads/news_file/seditajuxoruvulone.pdfIn PDF document text
    • https://akemi.ro/hirek/file/fafalapevoleleluzumog.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_off0000d529.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD529 10760 bytes
SHA-256: e0c29b9d56abd51e5df570207c6a8073d341503cfb3189af66e6c9a5a81e919e
font_01_sfnt_off0000edcc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEDCC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000105de.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x105DE 17204 bytes
SHA-256: 40126401687e3b0dceef9924d447d0b3b66d6f740ac78e04eb62db0a38c96477