Malicious PDF — malware analysis report

Static analysis result for SHA-256 c90b4bae708b7a21…

MALICIOUS

PDF

81.5 KB Created: 2021-08-25 17:52:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 560b960afd9b43485fbea10c44fda61e SHA-1: 425f5e3ceaa31692c3e048b2ac536f61ba8c4aaf SHA-256: c90b4bae708b7a21833535acfd676732e28209b55d7a29f426e3f6343e932f42
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload storage or disposable hosting, indicating a link farm designed to redirect users to malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware distribution. No scripts were extracted, but the structure and URL patterns are indicative of a malicious PDF.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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://krisoc.ru/uplcv?utm_term=english+speaking+questions+for+beginners PDF link annotation
    • http://ximangsongthao.com.vn/app/webroot/uploads/files/93337208614.pdfIn PDF document text
    • http://www.annaleehuber.com/content_files/file/raxukojadugukulanilitan.pdfIn PDF document text
    • http://rabotatver.ru/userfiles/admin/8815525559.pdfIn PDF document text
    • https://gamletaarnhuset.no/wp-content/plugins/formcraft/file-upload/server/content/files/160fcc2f01ef19---fituwaw.pdfIn PDF document text
    • https://autohausnschmidt.de/userfiles/file/nediworuvuditeduniso.pdfIn PDF document text
    • https://skyfireconsulting.com/wp-content/plugins/super-forms/uploads/php/files/4ksjruh6rsrgabia9rml3o6qhn/15613629525.pdfIn PDF document text
    • http://hydrem.ru/images/file/sifidifoponesaboxowuvi.pdfIn PDF document text
    • http://reginahajo.hu/_user/file/91525445573.pdfIn PDF document text
    • https://langumeistras.lt/i/File/94906692037.pdfIn PDF document text
    • http://komputerzagrosze.pl/userfiles/file/43249274777.pdfIn PDF document text
    • https://digireg.pl/upload/vojonofozerebubusuti.pdfIn PDF document text
    • http://www.lnk-creation.fr/upload/file/72628402212.pdfIn PDF document text
    • http://beetsom.com/PROGRAM_FCKeditor_UserFiles/file/178760256160e1583749677.pdfIn PDF document text
    • http://szpk.hu/_user/file/97989406499.pdfIn PDF document text
    • http://www.apsetedavisi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607fedbd0c4e2---51673250872.pdfIn PDF document text
    • https://www.allterra.group/wp-content/plugins/super-forms/uploads/php/files/9f25f879d1c5d19fdb2440fdf2a32c10/51106224412.pdfIn PDF document text
    • http://barudan.hk/UploadFile/file/20210725210320158.pdfIn PDF document text
    • http://asupuro.com/user_data/image//file/48103402900.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_off0000dafd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDAFD 17080 bytes
SHA-256: bfe2d0f932ab6d5479425b80e14e01371c8048387372ffdad496c822fdb574c0
font_01_sfnt_off0001077a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1077A 11100 bytes
SHA-256: 4e84a0a071497d09ce76e6db7264fbf71da332c9226d8d14da07d03bf1e3a105
font_02_sfnt_off000120be.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x120BE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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