Malicious PDF — malware analysis report

Static analysis result for SHA-256 631c0d4109f2e6dc…

MALICIOUS

PDF

84.8 KB Created: 2021-09-01 12:56:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 37db8ae0268376496582ea1beeb15d22 SHA-1: a8c07edb08310636934c22aa221bc6383598c677 SHA-256: 631c0d4109f2e6dcf5328f994608f647b9b9621faa4612f69f442ea63ade1249
156 Risk Score

Malware Insights

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

The PDF file was flagged by ClamAV as 'Pdf.Phishing.Trojan' and an ML classifier indicated a high probability of maliciousness. Heuristics identified it as a link farm, with many URLs pointing to compromised CMS upload directories. The document body is unreadable, but the presence of numerous external links suggests an attempt to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://nhatnamvina.vn/rich_editor/file/73773380517.pdf In PDF document text
    • https://maintogelonline.info/contents//files/35188621999.pdfIn PDF document text
    • https://nibrasimansch.com/userfiles/files/nosogopekupo.pdfIn PDF document text
    • https://yidinfo.net/wp-content/plugins/super-forms/uploads/php/files/r2g4o98a35kc8k4qp812ndtttm/ketav.pdfIn PDF document text
    • https://takiminsahada.com/wp-content/plugins/super-forms/uploads/php/files/qo565hksaid6fjjtkv4o3so10q/vozelifugokikosutev.pdfIn PDF document text
    • https://lllk.ru/wp-content/plugins/super-forms/uploads/php/files/48d9caa32797cfccf1d570df84186790/vepapupobeda.pdfIn PDF document text
    • http://lisahyatthealth.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a0c10941400---naluta.pdfIn PDF document text
    • http://conservationenergy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a856176e861---boligosirixu.pdfIn PDF document text
    • https://www.mclarenpress.com/wp-content/plugins/formcraft/file-upload/server/content/files/160875ea09ad3a---70049613554.pdfIn PDF document text
    • http://damoorefamilyreunion.com/clients/7/71/71c8bb141a0941b69292984b9770a174/File/83602959503.pdfIn PDF document text
    • http://modern-pro.ru/files/file/xobuwitizepu.pdfIn PDF document text
    • http://dgjst.com/upfile/file/57514359923.pdfIn PDF document text
    • http://moto-bike.pl/userfiles/file/72748762320.pdfIn PDF document text
    • http://kondicionery-vidnoe.ru/upload_picture/file/37301001663.pdfIn PDF document text
    • https://majubesar.org/contents//files/17382822072.pdfIn PDF document text
    • http://baheth24aqari.com/ckfinder/userfiles/files/7523771914.pdfIn PDF document text
    • https://ecef-groupe.com/wp-content/plugins/super-forms/uploads/php/files/d58gupvd0btd53vdfspktaa5n4/94046823314.pdfIn PDF document text
    • http://www.herbertvanderbrugghen.nl/draft/vugukoxesovulerafu.pdfIn PDF document text
    • https://detector-billetes.com/Imagenes/file/84368640756.pdfIn PDF document text
    • http://xn--kprq5pvqklteonubj6c.tw/CKEdit/upload/files/75080569696.pdfIn PDF document text
    • http://ristoranteibucanieri.it/userfiles/files/32240837037.pdfIn PDF document text
    • http://ibtaker.ps/userfiles/file/junixiwirefiware.pdfIn PDF document text
    • http://vipdiler.ru/files/file/kusabafagofininemufux.pdfIn PDF document text
    • http://vejwun.cz/images/35057007360.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/A3Ryygt5BCM/uplcv?utm_term=what+is+the+difference+between+a+solar+eclipse+and+lunar+eclipsePDF 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_off0000e50f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE50F 17520 bytes
SHA-256: 0433989ddea10f82661efd8a90fa777dedeffe418ae26d44c6b8723707843876
font_01_sfnt_off0001123c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1123C 11036 bytes
SHA-256: 73d0310a25ad7f53bc160ccb463afbc7ad7f45db3bf33e0db499f0ff98fb0d27
font_02_sfnt_off00012baf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12BAF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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