Malicious PDF — malware analysis report

Static analysis result for SHA-256 b8a91bb1be37a080…

MALICIOUS

PDF

80.5 KB Created: 2021-09-01 17:22:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 3f0dc8c093813df33876cdd47d2532a9 SHA-1: d048a83ad694795ad71e641bf3b77a12170afce4 SHA-256: b8a91bb1be37a08099c0da0131df206cef97bf795d58420e97f58b2aa2406f38
176 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF document that contains numerous embedded URLs, many of which point to compromised WordPress sites and disposable hosting. The heuristic 'SE_CALLBACK_LURE' suggests the document may be designed to trick users into calling a phone number, consistent with phishing or tech-support scams. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9944

Heuristics 7

  • 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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • 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://laborke.ru/uplcv?utm_term=ca+commercial+lease+agreement+pdf PDF link annotation
    • http://www.realisthotel.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ce2f7d9ce2e---93194381443.pdfIn PDF document text
    • http://markasib.ru/ckfinder/userfiles/files/27569691473.pdfIn PDF document text
    • http://bbdecontra.com/userfiles/files/42129919849.pdfIn PDF document text
    • https://creationstationdance.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609020906b6ef---96235577553.pdfIn PDF document text
    • http://www.sunarsurdurulebilir.com/wp-content/plugins/super-forms/uploads/php/files/9of5ni4cqpdgqgh3pip6ro4fv5/nuwemutiteke.pdfIn PDF document text
    • http://manpukuorder.com/uploads/files/rusejuzezolujusazunopuxe.pdfIn PDF document text
    • http://mattstergamer.com/wp-content/plugins/super-forms/uploads/php/files/ja6nojtghhgc756i86vgf72uug/negixitovejowivuj.pdfIn PDF document text
    • https://www.baileysmilk.com/wp-content/plugins/super-forms/uploads/php/files/d7db328d9e64815834159e728c5ba3c0/55073026470.pdfIn PDF document text
    • https://dezsredstvompx.ru/wp-content/plugins/super-forms/uploads/php/files/47d875527d2640895750b19f15617f04/wotewemurelukomafiz.pdfIn PDF document text
    • https://giridhareye.org/ckfinder/userfiles/files/40524420185.pdfIn PDF document text
    • https://razdolle.by/wp-content/plugins/super-forms/uploads/php/files/ntlq40hc9nijdu5u73cf6bf006/21822450637.pdfIn PDF document text
    • https://esprimagroup.com/userfiles/file/tetapupovosa.pdfIn PDF document text
    • https://ehblending.com/wp-content/plugins/super-forms/uploads/php/files/456b1704d156a97eb43248d31d482570/42205260955.pdfIn PDF document text
    • http://esteticka-stomatologie.cz/files/content/file/43048310756.pdfIn PDF document text
    • http://sin-hua.org/userfiles/torupivikefinarazerulido.pdfIn PDF document text
    • http://tangneylaw.com/admin/images/file/lasemizibalibi.pdfIn PDF document text
    • https://glosunspa.com/wp-content/plugins/formcraft/file-upload/server/content/files/160feda0e3073d---68382266506.pdfIn PDF document text
    • https://gz-topstar.com/wp-content/plugins/super-forms/uploads/php/files/1c02388f3f2ce475a12b4d8d69b43130/fulabeke.pdfIn PDF document text
    • https://www.brunosistemi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612140ed9d722---62720380951.pdfIn PDF document text
    • http://admio.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16076981c5b9ec---13330992438.pdfIn PDF document text
    • https://elicopter-de-inchiriat.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160e585804191d---28244563556.pdfIn PDF document text
    • https://bfull.ru/uploads/files/zozirul.pdfIn PDF document text
    • https://abe-rdc.com/userfiles/file/59601750940.pdfIn PDF document text
    • https://www.crossfitparamaribo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607b52533fcc6---72704787882.pdfIn PDF document text
    • https://ancoraeducacion.com/images/gebomeborufawazaxe.pdfIn PDF document text
    • https://malayalamfoundation.org/admin/my_files/file/jirebituburojekibodadi.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_off0000d531.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD531 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ed48.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED48 10996 bytes
SHA-256: 3a705525c4af947ec119f7f99eafd00be43d61ef7384b51fa4722607cde38bc5
font_02_sfnt_off00010692.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10692 17416 bytes
SHA-256: 5fbe08d8fb5c126c10d4422f90f68a2d03cf30db4c967ef14804380e2c2b9dce

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