Malicious PDF — malware analysis report

Static analysis result for SHA-256 9b35c18d09a28432…

MALICIOUS

PDF

78.5 KB Created: 2021-09-20 10:00:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 2e52dab2c42c087bfeb773237087fed4 SHA-1: 5ef393c75e06293e87ff46a1dd7a70c8e6ead9b8 SHA-256: 9b35c18d09a2843213d1d9d6978684a56a19f8b074db3ab521ff06919849ae6d
96 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised websites or domains designed for SEO spam. The ML classifier strongly indicates maliciousness, and the heuristic firings confirm the presence of a link farm, some of which are hosted on potentially compromised CMS uploads. The document body is heavily obfuscated and unreadable, providing no direct clues about its intent beyond the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • 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=bumblebee+streaming+vf PDF link annotation
    • http://www.investinwielkopolska.pl/application/lib/ckfinder/userfiles/files/14004709557.pdfIn PDF document text
    • https://munis-roquesalbes.cat/demo/vilalba/imatges/file/nijom.pdfIn PDF document text
    • https://wacee.net/wp-content/plugins/formcraft/file-upload/server/content/files/16130b20c5fe40---vetatamiborolemavujod.pdfIn PDF document text
    • http://likebarcode.com/image/files/20210910_235842.pdfIn PDF document text
    • http://namuvaldymas.lt/userfiles/file/faxovanunaxapetepi.pdfIn PDF document text
    • http://car-zone.sk/data/data/file/72139965494.pdfIn PDF document text
    • https://hattshopping.com/admin/assets/images/ckfiles/30920937057.pdfIn PDF document text
    • http://auto-rad.pl/userfiles/file/47428628109.pdfIn PDF document text
    • http://samtle.net/ckupload/files/71906079445.pdfIn PDF document text
    • http://skinct.com/upload_file/file/Fl202109180952518349.pdfIn PDF document text
    • http://chamdure.com/DATA/files/86972947420.pdfIn PDF document text
    • https://labelmarket.pl/data/file/fodem.pdfIn PDF document text
    • http://sarahscupcakery.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613bd52a01182---kinanemoxinubaze.pdfIn PDF document text
    • https://immo-cjeanpaul.lu/userfiles/files/jilegibirefodev.pdfIn PDF document text
    • http://ana-jsc.com/upload/files/lufemegovurabejabef.pdfIn PDF document text
    • http://locthanhroyal.com/upload/files/61656349081.pdfIn PDF document text
    • https://dtd.com.pk/ckfinder/userfiles/files/59827414210.pdfIn PDF document text
    • http://www.musicmaestrodiscos.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1612ec5ed47274---64748616565.pdfIn PDF document text
    • https://sofanet.ro/ckfinder/userfiles/files/40397173155.pdfIn PDF document text
    • https://rm-parketi.si/uploads/51163141262.pdfIn PDF document text
    • http://f-okinawa.com/img/tmp/files/17534524017.pdfIn PDF document text
    • http://autothudo.vn/upload/fck/file/ridamos.pdfIn PDF document text
    • https://sistemagestiondpr.co/userfiles/file/dasimaro.pdfIn PDF document text
    • http://ongxoanhdpe.vn/upload/files/93343147861.pdfIn PDF document text
    • http://www.vitrierbxl.be/wp-content/plugins/formcraft/file-upload/server/content/files/16132e0195aa7e---17724354918.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_off0000cb0a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB0A 10796 bytes
SHA-256: e3aca70fceab6f9bb3fbf43f8d96857e3950e75e3f26930d21ce78ebb5005be2
font_01_sfnt_off0000e3f1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3F1 18708 bytes
SHA-256: eb3e3e682eff36beb53e5ba6dfc3cc88966e510b68358f6f86496c59d57d8c02
font_02_sfnt_off0001145a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1145A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1