Malicious PDF — malware analysis report

Static analysis result for SHA-256 c3f9c4f10de27e83…

MALICIOUS

PDF

77.1 KB Created: 2021-08-22 04:01:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 4a52211fb898e388c82b733bb2fa152d SHA-1: 75c2940b597794f2d3295629171df904a9326b2f SHA-256: c3f9c4f10de27e835c4204c212f3afb3898b7242f3d52b9e48555391f8712758
156 Risk Score

Malware Insights

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

The PDF contains numerous external URIs and links to compromised WordPress upload directories, suggesting it functions as a link farm. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The presence of multiple distinct hosts and the use of 'utm_term' parameters in some URLs point towards a coordinated effort to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9840

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://pixomot.ru/uplcv?utm_term=capital+letters+and+full+stops+worksheet+with+answers PDF link annotation
    • https://www.advids.io/wp-content/plugins/formcraft/file-upload/server/content/files/16080a0b599860---57457544630.pdfIn PDF document text
    • https://1sis.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d8ae8222fa9---wusetetujijo.pdfIn PDF document text
    • http://svazekobciorlice.cz/userfiles/file/49289999744.pdfIn PDF document text
    • http://adhdadvisory.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607983d9bdc33---kilozalejutabagirokaze.pdfIn PDF document text
    • http://csc025.com/userfiles/file/20210615014855_c3vy7p.pdfIn PDF document text
    • http://nowyhotelik.pl/userfiles/file/57185038524.pdfIn PDF document text
    • http://doradcyprawni.com/images/pliki/1115305122.pdfIn PDF document text
    • https://buddingheights.org/wp-content/plugins/formcraft/file-upload/server/content/files/160a16af7c61cc---zezuzufuterejemubirinemav.pdfIn PDF document text
    • http://arci-mp.fr/admin/File/jewinivelig.pdfIn PDF document text
    • http://pivotal-technologies.com/userfiles/file/gapefidorakixakopexa.pdfIn PDF document text
    • http://4reality.cz/userfiles/files/dakexug.pdfIn PDF document text
    • http://clean-ecology.com/Upload/files/kuvitijisakigenav.pdfIn PDF document text
    • https://phase1acoustics.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608193b1c29c8---17572457757.pdfIn PDF document text
    • http://abwalabamaave.com/uploads/files/jesuzufojezinisigeg.pdfIn PDF document text
    • https://meesens.be/KrMee/Tekstverwerker/sixepubefezifetobune.pdfIn PDF document text
    • http://heureka-cz.eu/files/65641319684.pdfIn PDF document text
    • http://edu-family72.ru/content/images/uploads/file/74335387736.pdfIn PDF document text
    • http://pvsystreports.com/wp-content/plugins/super-forms/uploads/php/files/0pkpnoob1u7ll278trtk9qf236/dotofelotesanovin.pdfIn PDF document text
    • http://senseoftourism.dk/userfiles/file/66909346493.pdfIn PDF document text
    • http://lamekatus.ee/uploads/ckeditor/files/fozunefesawex.pdfIn PDF document text
    • https://antoinepanau.com/wp-content/plugins/super-forms/uploads/php/files/9f92a4bb04642da04e391c1457e8738e/galofilurobu.pdfIn PDF document text
    • http://ledson.ru/upload_picture/78875085272.pdfIn PDF document text
    • http://aksaaydinlatma.com/img/editor/image/file/32258900083.pdfIn PDF document text
    • http://kassa.pl/userfiles/file/mutibifiv.pdfIn PDF document text
    • http://presssimayeshahr.ir/pic/file/86897809286.pdfIn PDF document text
    • http://tasarimak.com/ckfinder/userfiles/files/lenomunilivilup.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_off0000c943.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC943 17080 bytes
SHA-256: 2c0630c86cb46b6c66ebef5135abe11039f97b8f98e4bea2815412edc23a66b7
font_01_sfnt_off0000f54a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF54A 10904 bytes
SHA-256: a9a0b191c50eabd748f422b8e27659ee8562b304b5c3925c7116a8483b2f9aa9
font_02_sfnt_off00010e93.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E93 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1