Malicious PDF — malware analysis report

Static analysis result for SHA-256 23a0941e355ec06f…

MALICIOUS

PDF

95.7 KB Created: 2021-08-18 10:24:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: b9b4f1bb49d3d8090e22aec4da2a131e SHA-1: e48a5bbeecbe9d9bee35db95212d78442cf0c915 SHA-256: 23a0941e355ec06f44f8518045cf06f3441067f6e459f3a873db704e99d25cdd
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It functions as a link farm, directing users to multiple compromised CMS upload locations, likely for phishing or malware distribution. The presence of numerous unknown URLs associated with compromised WordPress installations supports this conclusion.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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://www.oschouston.com/osc/wp-content/plugins/formcraft/file-upload/server/content/files/1609002ab90ed4---33111580830.pdf In PDF document text
    • http://eminenceinc.com/userfiles/file/sodumawixirukiteg.pdfIn PDF document text
    • https://hmjrgoldhockey.org/wp-content/plugins/super-forms/uploads/php/files/086ea532c064638779c3b73c39858a85/vefujosuvusawifawi.pdfIn PDF document text
    • http://iideree.org/wp-content/plugins/formcraft/file-upload/server/content/files/160a149a05247c---nepoberigiwiwiporesituf.pdfIn PDF document text
    • http://aristosaigonhotel.com/uploads/files/tenoro.pdfIn PDF document text
    • https://guapa2.com/admin/fck/file/44640863993.pdfIn PDF document text
    • https://www.dentaltaxpros.com/wp-content/plugins/super-forms/uploads/php/files/b3068bc191b1f93445bcd22230ed7cea/93939046151.pdfIn PDF document text
    • https://www.die-umzugsfabrik.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d4c1067b2b3---121859138.pdfIn PDF document text
    • http://www.publicitymailing.ie/wp-content/plugins/formcraft/file-upload/server/content/files/160768b25617ee---sodejagubifuvowod.pdfIn PDF document text
    • http://oshcongregation.com/userfiles/file/49385678426.pdfIn PDF document text
    • http://studiolegalezullo.eu/userfiles/files/xodetupizevo.pdfIn PDF document text
    • https://hotelritariccione.it/wp-content/plugins/formcraft/file-upload/server/content/files/1609a678c700b7---86167387.pdfIn PDF document text
    • https://wcdt.co.th/wp-content/plugins/super-forms/uploads/php/files/bdgcbefgo6kcif4mi852slgn8a/21084929786.pdfIn PDF document text
    • http://villaturri.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609bd267bc931---velidepezinidowadonej.pdfIn PDF document text
    • http://plafondchauffant.fr//img/user/file/nizagak.pdfIn PDF document text
    • https://masterjobintl.com/ckfinder/userfiles/files/47890193662.pdfIn PDF document text
    • https://pmeds.us/userfiles/file/49287855521.pdfIn PDF document text
    • http://ganan10.co.il/wp-content/plugins/formcraft/file-upload/server/content/files/16075edb00a9e0---jalavoji.pdfIn PDF document text
    • http://makaeximworld.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078fab8d270e---99035257821.pdfIn PDF document text
    • http://botosani.ro/img/uploads/file/sitadokunu.pdfIn PDF document text
    • https://www.dekleinewerf.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1609bc48b3a7a3---mutodejenewevabupe.pdfIn PDF document text
    • https://thebillionbottom.com/business_school/uploads/file/fowodamuxexojijo.pdfIn PDF document text
    • http://fredericjean.net/oplusco/file/zixisodasek.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1xuhb7AK25c/uplcv?utm_term=is+acca+recognized+in+usaPDF 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_off00011088.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11088 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0001289f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1289F 10512 bytes
SHA-256: 6763b7352bf12c381fd9ad2e4def2f47c0c4d26bfeed2e869af338774e8e10c1
font_02_sfnt_off00014070.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14070 18176 bytes
SHA-256: dc7c033b9e9e95c3417a6c5a8b9bf77dc74f7e109fb9a4d80728bf9c823a4f68