Malicious PDF — malware analysis report

Static analysis result for SHA-256 87f5b3df18b2bc2a…

MALICIOUS

PDF

71.5 KB Created: 2021-09-01 20:46:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: a2ec9724953e07615645f86e98c8ff1b SHA-1: 037642b01f0df74628145394b1e0fe4a54b3c7b9 SHA-256: 87f5b3df18b2bc2ab46b0bee5c11d17dd08f92500a4c9edc324c57a16ecd0bbe
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file contains embedded JavaScript, which is a common technique for executing malicious code. The file also exhibits characteristics of a link farm, pointing to multiple compromised websites, likely to obscure the ultimate destination and evade detection. The ClamAV detection and ML classifier strongly indicate malicious intent, consistent with phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 7

  • 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.
  • 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://krisoc.ru/uplcv?utm_term=regression+equation+of+y+on+x+example PDF link annotation
    • https://kisikana.hr/userfiles/file/pulogigorat.pdfIn PDF document text
    • https://www.tifdip.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078f202070a4---farotezofuduzerebasaz.pdfIn PDF document text
    • https://burgas-remonti.com/userfiles/file/jonelovubewumixalu.pdfIn PDF document text
    • https://michaels-limo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a416b1261ab---61371569640.pdfIn PDF document text
    • https://fmpride.com/wp-content/plugins/super-forms/uploads/php/files/a338f21cebbca5397f8280712a0ae6a1/gibufobogezoson.pdfIn PDF document text
    • http://frezerovka.by/images/fxeditor/file/setowupazal.pdfIn PDF document text
    • https://www.idromeccanicasrl.com/idromeccanicasrl.com/wp-content/plugins/super-forms/uploads/php/files/585ee157e088194be566de8415d619f6/26610684363.pdfIn PDF document text
    • http://beijinghuojia.cn/userfiles/file/97223878599.pdfIn PDF document text
    • https://www.certificagreen.com/wp-content/plugins/formcraft/file-upload/server/content/files/16077fed6b44a2---68264412699.pdfIn PDF document text
    • http://www.jcca.co.in/wp-content/plugins/formcraft/file-upload/server/content/files/16084479f37606---kenowakemoxumaleregokun.pdfIn PDF document text
    • http://factory-01.com/js/upload/files/fotexaxamasokuzewadaf.pdfIn PDF document text
    • http://apexnepaltravel.com/userfiles/file/zedipog.pdfIn PDF document text
    • https://agribusiness.pk/wp-content/plugins/formcraft/file-upload/server/content/files/16128cb2f45959---jivizowexebedonatide.pdfIn PDF document text
    • https://sk-developers.com/wp-content/plugins/formcraft/file-upload/server/content/files/16083bfe873a5e---duganew.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_off0000b47a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB47A 11208 bytes
SHA-256: 80fe5774cc9645da9f48df563806280550869009752ba72a7b9ba857c4fe8911
font_01_sfnt_off0000ce6b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCE6B 16608 bytes
SHA-256: 7ed14f261b37cc54f30a45f89e26b8f0a86fc63c8b76ba759e1dbb44be3f1e19
font_02_sfnt_off0000f905.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF905 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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