Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8dcd0f713e84151…

MALICIOUS

PDF

88.1 KB Created: 2021-09-18 15:38:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 3af915d3c3f1888416f318460166c4c8 SHA-1: 5e07b2db98fb247c04e0b46972dc402a80862b88 SHA-256: a8dcd0f713e84151846a212d6a24f802ebd9b819be86c219ad928ca287ca7453
156 Risk Score

Malware Insights

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

The PDF contains numerous external links, many hosted on compromised or disposable domains, indicating a link farm or redirection scheme. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery. The presence of PDF-specific heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' further supports this, pointing towards an attempt to obscure the final malicious destination.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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 https://krisoc.ru/uplcv?utm_term=a+sentence+with+the+word PDF link annotation
    • http://soundspace.eu/Upload/file/bisevug.pdfIn PDF document text
    • https://francois-daulte.com/ckfinder/userfiles/files/52189476739.pdfIn PDF document text
    • http://idealthailand.com/file_media/file_image/file/29047867573.pdfIn PDF document text
    • http://bannermaul.com/userData/board/file/65761710763.pdfIn PDF document text
    • https://4wheelchile.cl/admin/uploads/file/rejuwu.pdfIn PDF document text
    • http://ha-sine.com/d/files/81167856930.pdfIn PDF document text
    • https://yumasri.com/assets/ckfinder/userfiles/files/tijadeseratokuguwofuwiru.pdfIn PDF document text
    • http://limeitec.com/upfiles/editor/files/zizum.pdfIn PDF document text
    • http://coaching-scolaire.net/userfiles/file/80457384273.pdfIn PDF document text
    • https://ltes.tw-goods.com/UserFiles/files/41133103316.pdfIn PDF document text
    • http://peoplefineart.com/assets/202109/files/20210914143010643198.pdfIn PDF document text
    • http://the100voicesofgospel.ch/fichiers/newsletter/file/katofasinu.pdfIn PDF document text
    • https://zifu-tech.com/app/webroot/userfiles/files/1758626947.pdfIn PDF document text
    • https://travels-ukraine.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613cc6f109b18---sivifetanuboxoxeresiwo.pdfIn PDF document text
    • https://glearningsolutions.com/userfiles/files/19888034649.pdfIn PDF document text
    • https://filetorme.com/upload/files/sifarufifibomuv.pdfIn PDF document text
    • http://himalayakebab.irafbrothers.com/shipinc/userfiles/files/desejef.pdfIn PDF document text
    • http://www.fullertherapy.com/wp-content/plugins/formcraft/file-upload/server/content/files/16131ab2f6eecc---kobiresibasuneduke.pdfIn PDF document text
    • https://cdmsig.com/ckfinder/userfiles/files/1584564090.pdfIn PDF document text
    • http://aaaexpressac.com/userfiles/file/45356365766.pdfIn PDF document text
    • http://kaufdeinauto.de/wp-content/plugins/formcraft/file-upload/server/content/files/16142afc799d0f---misina.pdfIn PDF document text
    • https://optimuselearningschool.aels.edu/learning/site/images/uploadfiles/91028570595.pdfIn PDF document text
    • http://giftboxvietthuy.com/upload/ck/files/velubuforegejijofatira.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_off0000f380.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF380 10328 bytes
SHA-256: 12ca40d4880017b6559fd0c683fbf3fbb68a373d35fe3e4414947a98b7e57591
font_01_sfnt_off00010ad8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10AD8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000122ea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x122EA 18520 bytes
SHA-256: 6117e983ed2228fa2b2208b14d5d3646eca5644314323a1378b18963554d9e69

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