Malicious PDF — malware analysis report

Static analysis result for SHA-256 135f4b9622adfd98…

MALICIOUS

PDF

68.5 KB Created: 2021-09-22 14:37:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 9acce2adbe0f2f043ae372760a8c8acb SHA-1: 87a1b3509ce8bcc4d38a4d31b3488fb4a20ec399 SHA-256: 135f4b9622adfd98440b5e4d977075659072c1d4776aeec6c07da9b6447d9483
156 Risk Score

Malware Insights

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

The file was detected by ClamAV as Pdf.Phishing.Trojan and flagged by an ML classifier, indicating malicious intent. It contains numerous links pointing to compromised websites and disposable hosting, suggesting a phishing or malware distribution scheme. The presence of external URI links and a link farm on compromised CMS upload storage strongly supports this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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 https://towa-aaa.jp/userfiles/file/nasosuxibufikakesezesovi.pdf In PDF document text
    • https://aldurra.ly/images-editeur/img/file/72167288366.pdfIn PDF document text
    • http://greddy.com/admin/common/ckfinder/userfiles/File/kajizufagururolozipufuk.pdfIn PDF document text
    • http://duancanhotot.com/upload/files/51688325408.pdfIn PDF document text
    • http://www.fashiongale.ro/userfiles/files/66056227717.pdfIn PDF document text
    • http://www.travelwithtaangoo.com/img/file/91035399486.pdfIn PDF document text
    • http://caribsplash.org/wp-content/plugins/formcraft/file-upload/server/content/files/1613d120d09c97---xumuwoneba.pdfIn PDF document text
    • http://shipsupply.ru/userfiles/files/renajategobujatipaxaboduf.pdfIn PDF document text
    • http://nuuts.mn/uploads/assets/37022003565.pdfIn PDF document text
    • https://akanaymatbaa.com/calisma2/files/uploads/70922268681.pdfIn PDF document text
    • http://suranareecommand.net/UserFiles/File/zasefabirexexiwut.pdfIn PDF document text
    • https://vieclamlaocai.vn/webroot/img/files/wuzuzumubeju.pdfIn PDF document text
    • https://www.histoiresdegroupes.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613492b8a7009---lifar.pdfIn PDF document text
    • https://siphouse96.com/wp-content/plugins/super-forms/uploads/php/files/5f992c8adf619ac3282202902e5c48e6/daxojixakudolumemedetox.pdfIn PDF document text
    • http://szm.hu/userfiles/file/89482041985.pdfIn PDF document text
    • http://xn--12cfu9bc1efac9a9azfdsb7b9d1f0j.net/ckfinder/userfiles/files/zufotavevejabotituz.pdfIn PDF document text
    • http://hotelniagararimini.eu/userfiles/files/nogevofexataze.pdfIn PDF document text
    • https://lnpro.in/ckfinder/userfiles/files/wosedi.pdfIn PDF document text
    • https://pensiuneavalentina.ro/app/webroot/file/zopiwaxakobosisexunabis.pdfIn PDF document text
    • http://gestioniarmatoriali.it/mamuregatete.pdfIn PDF document text
    • http://guojingmall.com/userfiles/file///kafiduzirelezeroporonuxi.pdfIn PDF document text
    • https://crossfitbeeshark.ro/app/webroot/files/userfiles/files/lenudare.pdfIn PDF document text
    • https://nuevocoach.co.uk/wp-content/plugins/super-forms/uploads/php/files/741bc32a6c712adcb7ad967b471db245/93018583996.pdfIn PDF document text
    • https://www.geya99.com/ckfinder/userfiles/files/16732439835.pdfIn PDF document text
    • http://nhadeptannguyen.com/uploads/files/73529933444.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/LPIa9PGmDLg/uplcv?utm_term=pgp+android+mailPDF 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_off0000b15d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB15D 14576 bytes
SHA-256: cefe0c8f9b9a53449c8a646e188921a1c54e81c3eb529dfa466c2d829508b46c
font_01_sfnt_off0000d5d9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD5D9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000edf0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEDF0 10336 bytes
SHA-256: 2cf7bf1b666354f04511c5fee8a5aee3347f8bb6cacc3b8acf8272cd396ff392