Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4931563b6f679e4…

MALICIOUS

PDF

80.5 KB Created: 2021-09-13 16:31:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 73ef0a03b5a56aec59f242b62f8c938d SHA-1: 77be5b2dd3d5cf44cc6240209a87d019bd475ea6 SHA-256: b4931563b6f679e44da3eb4abd2329c5791bad1d862b44d19795774659e7331f
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains numerous links to external URLs, many of which are hosted on disposable domains and appear to be part of a link farm. The heuristic 'PDF_RANDOM_URL_LINK' specifically flags a link to a PDF file on a suspicious domain, indicating a likely attempt to serve a second-stage payload. The ML classifier and ClamAV detection strongly support the malicious nature of this file.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://alotercuman.com/ckfinder/userfiles/files/86091453951.pdf In PDF document text
    • http://kanoonkaraj.ir/dbmanager/filebank/htmlgallery/file///57382764589.pdfIn PDF document text
    • https://k85shj16h-561lt.com/contents/files/52952994902.pdfIn PDF document text
    • http://www.sunarnuricomuisvealisverismerkezi.com/wp-content/plugins/super-forms/uploads/php/files/dl6iug1vi5bb90c802s4q3q2p7/mabuletebaseditexujugoj.pdfIn PDF document text
    • https://lidiyageorgieva.com/ckfinder/userfiles/files/furusiziwalebivajufe.pdfIn PDF document text
    • http://kcpsystem.com/userData/board/file/99527950137.pdfIn PDF document text
    • http://zzps.pl/userfiles/file/juwitilasalojad.pdfIn PDF document text
    • http://s2ipower.com/survey/userfiles/files/89053561614.pdfIn PDF document text
    • https://tortugafilms.ca/adminfiles/file/pevorokujarodila.pdfIn PDF document text
    • http://marasintl.com/public/ckfinderuploads/files/konebiwetamosu.pdfIn PDF document text
    • https://dycmc.com/DATA/upload/files/202109081101233904.pdfIn PDF document text
    • http://trevelci.ru/ckfinder/userfiles/files/nipegoke.pdfIn PDF document text
    • http://superazs.ru/images/news/file/10829759446.pdfIn PDF document text
    • http://kowel.com/ckfinder/userfiles/files/1631514547.pdfIn PDF document text
    • http://3bbb.fr/ckeditor/upload/files/69290370848.pdfIn PDF document text
    • http://vuatoyen.com/uploads/userfiles/file/70839762854.pdfIn PDF document text
    • https://nothingbutsafetyglasses.com/userfiles/file/sukozatagenixoro.pdfIn PDF document text
    • http://klgd.spokoino.ru/i/upload/files/53214532190.pdfIn PDF document text
    • http://grani-tonkogo-mira.ru/wp-content/plugins/super-forms/uploads/php/files/cbbb0d8fcce5c5c903eb5dcc63763d6b/zasodabemubejozoxezuraji.pdfIn PDF document text
    • http://mclarenquartz.in/ci/userfiles/files/nudaral.pdfIn PDF document text
    • http://sintniklaas.kinderopvangpimpeloentje.be/ckfinder/userfiles/files/fibunem.pdfIn PDF document text
    • http://didaconcept.com/admin/fckeditor/file/vataziduronegewut.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/A3Ryygt5BCM/uplcv?utm_term=my+sister+the+vampire+books+read+online+for+freePDF 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_off0000d5a7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD5A7 17480 bytes
SHA-256: a95a465972c2d23599d34cc1071c92580fd6583c71459ecb12fdd0204bdd9cb4
font_01_sfnt_off0001030b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1030B 11168 bytes
SHA-256: 290492a685f16fa5ebf5d9058e81d589e568130f159cc2d9b1b047112e21c348
font_02_sfnt_off00011cc8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11CC8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1