Malicious PDF — malware analysis report

Static analysis result for SHA-256 51471d5873d9f401…

MALICIOUS

PDF

83.1 KB Created: 2021-09-11 00:47:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: dfcb96c8b510582616713b633b969e79 SHA-1: 41c5cfa45427011e9e54be3babd670b07ca3e120 SHA-256: 51471d5873d9f4018ea66987aff030883350128d4d464de24bc6c35d9436bd3c
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, many of which point to PDF files hosted on various domains, suggesting a link farm or redirection mechanism. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating a tactic to obscure the true destination. While no scripts were explicitly extracted, the PDF structure and embedded URLs suggest it's designed to lead the user to external, potentially malicious, content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://jmk.kr/ckfinder/userfiles/files/bejipenakobimiregav.pdf In PDF document text
    • http://philipp-haberland.de/images/upload/file/5508768739.pdfIn PDF document text
    • https://optimuselearningschool.aels.edu/learning/site/images/uploadfiles/55755671962.pdfIn PDF document text
    • https://northwestconvention.cz/data/files/muligo.pdfIn PDF document text
    • https://ev-owners.jp/userfiles/files/40112952361.pdfIn PDF document text
    • http://tangiahoang.vn/Images_upload/files/58113725691.pdfIn PDF document text
    • https://cs-nippon-cp.com/mailmagazine/upload/files/wubem.pdfIn PDF document text
    • http://self119.net/upload/userfiles/2021/09/files/210901114550.pdfIn PDF document text
    • http://argra.rs/wp-content/plugins/formcraft/file-upload/server/content/files/16138a9852acdd---90959929845.pdfIn PDF document text
    • https://testgit.begurholidays.com/uploads/userfiles/files/polewugezaxolomolidumalir.pdfIn PDF document text
    • http://savytrading.com/userfiles/file/9277548872.pdfIn PDF document text
    • http://panda-es.tokyo/yamituki-n/uploads/files/nivakadugosazigalesawase.pdfIn PDF document text
    • http://matras-devison.ru/upload/file/defiwuwofegurexu.pdfIn PDF document text
    • http://fszhenjia.com/upfolder/e/files/20210909125909.pdfIn PDF document text
    • https://autoradiator.mn/uploads/ckfinder/files/61590539718.pdfIn PDF document text
    • http://7seapharmtech.com/Uploadfiles/files/50138162268.pdfIn PDF document text
    • http://gaestehaus-am-erlkoenig.de/img/editor/file/50010019390.pdfIn PDF document text
    • https://groupekheidri.com/ckfinder/userfiles/files/besive.pdfIn PDF document text
    • https://kakakmanis.com/contents/files/sinovenamilikotepaxoxuwu.pdfIn PDF document text
    • http://shepardinteriordesign.com/rw/upload/file/kalagenugosivukagupuki.pdfIn PDF document text
    • http://sanmorales.es/userfiles/files/xapuwalowuli.pdfIn PDF document text
    • http://marienoellebermond.com/img/uploaded/file/wiruveda.pdfIn PDF document text
    • http://ceramkgres.ru/userfiles/file/xaxaduvijopagoje.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/S30rS-6n6vg/uplcv?utm_term=mods+para+craftsman+apkPDF 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_off0000dfb7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFB7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f7ce.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF7CE 10596 bytes
SHA-256: bab1440f918c75a9a25e17b7ea3cc44358c80b154cc6b35eafefafa0e34d6b09
font_02_sfnt_off00011003.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11003 18112 bytes
SHA-256: 58d01082eb5d2f43a3bf30943307310548f15834e7f80ee53f76bbfc86eef032