Malicious PDF — malware analysis report

Static analysis result for SHA-256 51843b0403c3f6dd…

MALICIOUS

PDF

81.3 KB Created: 2021-09-16 08:34:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: d6acb3b978ca7944b250dc79b8b420c0 SHA-1: 120e5cd6fa82ca4ac7eaf86cec349507382a797b SHA-256: 51843b0403c3f6dd2e21da0561c137ece4fdd34f932477c127ed5f872f06adc3
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by ClamAV as 'Pdf.Phishing.Trojan' and an ML classifier indicated a high probability of maliciousness. Heuristics identified it as a link farm, with several URLs pointing to compromised WordPress upload directories and disposable hosting. This suggests the document is designed to lure users to malicious sites, likely for phishing or to download further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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 http://radio-salsa.com/php/rs/filesupload/file/12563663849.pdf In PDF document text
    • https://regiefranchet.fr/userfiles/files/bizagatokejasalivati.pdfIn PDF document text
    • https://careersourceokaloosawalton.com/files/public/61566542896.pdfIn PDF document text
    • http://italy-ex.com/images/blog/file/7098609006.pdfIn PDF document text
    • http://onnetsolution.in/userfiles/file/sikiseratukolopanilu.pdfIn PDF document text
    • https://www.entornopublicitario.com/wp-content/plugins/super-forms/uploads/php/files/c85dcb01d81149dc36b1df15945eeec5/fitejarusugodu.pdfIn PDF document text
    • http://sh-ruiyangcpa.com/userfiles/file/2021-9///20219285644706.pdfIn PDF document text
    • http://sspvjd.com/FileData/ckfinder/files/20210916_C038D57F6489A56B.pdfIn PDF document text
    • http://hotelamadeustorino.com/userfiles/files/28578920113.pdfIn PDF document text
    • https://wspaperbag.com/userfiles/file/19859830905.pdfIn PDF document text
    • https://rosebankprimary.co.za/inc/ckfinder/userfiles/files/nawufawuram.pdfIn PDF document text
    • https://bursac.net/userfiles/file/74783836432.pdfIn PDF document text
    • http://thai-apsproducts.com/file_media/file_image/file/lavosos.pdfIn PDF document text
    • http://americansemitruckparts.com/d/files/82137022797.pdfIn PDF document text
    • https://elpollopaulino.com/cenavarra_userfiles/files/xedejanilikisarepum.pdfIn PDF document text
    • https://www.phoenixdentalacademy.co.uk/wp-content/plugins/super-forms/uploads/php/files/eb034c6d5ef1a0fbcb50777d81b63490/75841749276.pdfIn PDF document text
    • https://topconta.ro/userfiles/file/noxaxom.pdfIn PDF document text
    • https://oolong-dining-co.com/webroot/editor-uploads/files/lozif.pdfIn PDF document text
    • https://cbdc.co/uploads/ckfinder/userfiles/files/50859074248.pdfIn PDF document text
    • https://galaxytraining.examinationonline.com/files/fiboraxorukibuforimajunu.pdfIn PDF document text
    • https://zilalcooling.com/other_files/File/dusakulanizemepegupumiki.pdfIn PDF document text
    • https://mercedesmazo.es/wp-content/plugins/formcraft/file-upload/server/content/files/1613503db43184---nubewezuxunuriloke.pdfIn PDF document text
    • http://www.medicalalliedtraining.com/wp-content/plugins/formcraft/file-upload/server/content/files/161361bb7e8f61---3673432012.pdfIn PDF document text
    • https://legouic-peinture.fr/userfiles/file/90806147364.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/6naE_Nh8_CY/uplcv?utm_term=ios+system+sound+id+listPDF link annotation
    • 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_off0000dac9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDAC9 17748 bytes
SHA-256: d57e50fab0634260e1b1b3bc4f78a932042ade8d4cfbfe3a0b9c9acab829b2a1
font_01_sfnt_off00010908.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10908 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001211f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1211F 10312 bytes
SHA-256: 0f2c54c742e1ac83a88baa26662ab3bb75d1a52889910e56a144e301fb664390