Malicious PDF — malware analysis report

Static analysis result for SHA-256 51ddd8a79541ee5c…

MALICIOUS

PDF

71.9 KB Created: 2021-10-01 08:59:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 4189c5cb5b5471514a99def1200b3b14 SHA-1: d36393bdfa830bba32a9fb8232d069f575631316 SHA-256: 51ddd8a79541ee5c2f447acb80c29e71c5e2779384292e2c8eccc1a68f6a248f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which are part of link farms hosted on disposable or compromised domains. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. While no scripts were explicitly extracted, the PDF structure and URL patterns are consistent with malicious document delivery mechanisms.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

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://laborke.ru/uplcv?utm_term=archive+messages+in+messenger+android PDF link annotation
    • http://khodahoanglang.com/admin/webroot/upload/image/files/jerujujapuxu.pdfIn PDF document text
    • https://coachtourbusrental.com/wp-content/plugins/formcraft/file-upload/server/content/files/16135284757d08---zipefubutitaxujowitaruwo.pdfIn PDF document text
    • http://jhdljz.com/userfiles/file/1631847987.pdfIn PDF document text
    • http://pilatesmystyle.com/userfiles/files/46224284871.pdfIn PDF document text
    • http://ltmetal.com/userfiles/files/palulikiwir.pdfIn PDF document text
    • https://speedwayinfo.hu/uploads/file/80007296955.pdfIn PDF document text
    • http://tomasmrazek.cz/userfiles/file/fuxebazu.pdfIn PDF document text
    • https://www.paseppe.gr/ckfinder/userfiles/files/jikoxasinasubaleb.pdfIn PDF document text
    • http://thingsantiquesla.com/userfiles/files/fedotuluvemowevipudimodam.pdfIn PDF document text
    • http://kibbkw.com/uploads/files/fugofuj.pdfIn PDF document text
    • http://www.rsvpcatering-ar.com/files/imagesfile/81563149720.pdfIn PDF document text
    • https://www.helpagesl.org/wp-content/plugins/formcraft/file-upload/server/content/files/16143777842886---88332194944.pdfIn PDF document text
    • http://lawyergz.net/uploadfile/files/kekisabiwaxatotevasa.pdfIn PDF document text
    • http://karmakonnect.org/DrumiBhatt/karmakonnect.org/Final/ckeditorimage/files/97638451128.pdfIn PDF document text
    • http://www.synagoge-stommeln.de/ckfinder/userfiles/files/sekozamivenu.pdfIn PDF document text
    • https://penmypoem.com/new/admin/uploadfiles/file/vuvegokigulosisezabanex.pdfIn PDF document text
    • https://medius.sk/userfiles/file/6946392044.pdfIn PDF document text
    • http://chipmax.in/chipmax/ckfinder/userfiles/files/39011334265.pdfIn PDF document text
    • http://dayuntang.com/assets/uploads/ckedit/files/20210905180503.pdfIn PDF document text
    • http://www.pirac.org/wp-content/plugins/super-forms/uploads/php/files/3d43464aa27b3ce93938a513fde45316/vepuwelaja.pdfIn PDF document text
    • https://www.ayersworthglen.com/wp-content/plugins/formcraft/file-upload/server/content/files/161343a6b6a625---juneliwop.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_off0000b2b6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB2B6 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cacd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCACD 10720 bytes
SHA-256: 71b8ea2d28aa88097b665cb940f170972dbd6c93dd66f8967fd45a4ba41f5923
font_02_sfnt_off0000e30e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE30E 18536 bytes
SHA-256: 06f1931c83750cecce12bd26653c495ded2e18cc808f2ec07747014a1de4c473