Malicious PDF — malware analysis report

Static analysis result for SHA-256 91635f4c0629b6cb…

MALICIOUS

PDF

76.5 KB Created: 2021-09-08 13:04:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 8425cb184918709dd6af94eed838325a SHA-1: 5daaf8bf52feaf26baca065d6a71139a9e69a394 SHA-256: 91635f4c0629b6cbb1a049f259c964eb5b85881b5e08ecb623a7d48c08353ebf
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to websites that appear to be part of a link farm, with some hosted on compromised CMS uploads or disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The presence of multiple link farm heuristics and the overall structure suggest a deliberate attempt to obscure the final destination or to leverage SEO tactics for malicious purposes.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://sunwisechem.com/Uploadfiles/files/24794231528.pdf In PDF document text
    • https://strings97.hu/userfiles/file/pilunafewavizab.pdfIn PDF document text
    • http://satcomlink.com/userData/board/file/46640191960.pdfIn PDF document text
    • http://genarchi.com/data/temp/file/gifonerulazisujep.pdfIn PDF document text
    • https://kvizek.hu/ckfinder/userfiles/files/lajaxodoweritemija.pdfIn PDF document text
    • http://vstarmp.cn/upload/files/20210901_102844.pdfIn PDF document text
    • https://siemreaptraveltours.com/userfiles/file/21712538742.pdfIn PDF document text
    • https://broadstripe.com/wp-content/plugins/super-forms/uploads/php/files/c20aaef277f7c4aeecc79b92904c5edd/9923000630.pdfIn PDF document text
    • http://www.onekaddy.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130afde87fb6---zejuvonami.pdfIn PDF document text
    • http://stepasidemedical.ie/images/uploads/file/fujedasexasamadipopasek.pdfIn PDF document text
    • http://wang023spa.com/userfiles/202109file/2021090710251270554.pdfIn PDF document text
    • https://luxurytravel-show.com/wp-content/plugins/super-forms/uploads/php/files/cc61ad9482e80cd6e28bc0c3563e4a65/jagadetomaromekulujobeg.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613289c703d61---geganijijaf.pdfIn PDF document text
    • http://www.grupoaccs.net/ckfinder/userfiles/files/dubes.pdfIn PDF document text
    • http://godsownproperties.com/userfiles/file/gapoxo.pdfIn PDF document text
    • https://coolingrealestate.com/your-home-cleaner/FCKuploads/file/91905758875.pdfIn PDF document text
    • http://baracenter.be/userfiles/file/rapoxowepizi.pdfIn PDF document text
    • https://kiofruits.com/admin/uploads/files/3440338362.pdfIn PDF document text
    • https://tradingphrases.net/userfiles/files/migumizozaradasatifasek.pdfIn PDF document text
    • https://anakmeong.com/contents/files/vunovebudil.pdfIn PDF document text
    • http://dworbieland.pl/userfiles/file/3630703180.pdfIn PDF document text
    • http://prplus4u.com/ckupload/files/29308109632.pdfIn PDF document text
    • http://reanda.com/jingkelun/userfiles/files/20210903231818.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/6naE_Nh8_CY/uplcv?utm_term=dodge+durango+2003+manualPDF 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_off0000c6a1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC6A1 10748 bytes
SHA-256: c0c9f3ab4508f5b2211239159c12cfb889990fc0730c232dd77836539ac34c5f
font_01_sfnt_off0000df1d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF1D 17428 bytes
SHA-256: d1cfc2ffce85bb012c7a1a343a3e9820ac9652314f8041d3aad83a3d1cb8183d
font_02_sfnt_off00010c5f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C5F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1