Malicious PDF — malware analysis report

Static analysis result for SHA-256 73bbfb87b3b22650…

MALICIOUS

PDF

73.1 KB Created: 2021-09-16 23:48:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 466381959d4c37eaa7434041edfc1bd3 SHA-1: 95ee814c206bc0a27d43ca9414832e3a85089456 SHA-256: 73bbfb87b3b22650166de2fd446860c4f00d35b9b3a32b043475ef8e4348b9f2
156 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics reveal it functions as a link farm, with numerous embedded URLs pointing to compromised CMS uploads and disposable domains. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

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://irlanc.ru/uplcv?utm_term=i9060i+root+file PDF link annotation
    • http://komodovo.ru/upload_picture/zadagusenujafetolukilunek.pdfIn PDF document text
    • http://akbmodel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613dcdd29b2e6---pejikogatuki.pdfIn PDF document text
    • http://ks-system.co.uk/ckfinder/userfiles/files/migudokubotudaru.pdfIn PDF document text
    • http://ei-windykacja.pl/upload/file/53480409296.pdfIn PDF document text
    • http://orthopediedelft.eu/files/lefexidofupexi.pdfIn PDF document text
    • http://tagsu.com/attachments/fckattachments/file/27783210697.pdfIn PDF document text
    • http://capitaloffice.pl/fotki/file/rirurupobozu.pdfIn PDF document text
    • https://alhasooncorp.com/Files/files/delefi.pdfIn PDF document text
    • http://warmistore.com/userfiles/file/77801624750.pdfIn PDF document text
    • https://arizonapoolcontractor.com/wp-content/plugins/formcraft/file-upload/server/content/files/16133eb1b9e5e1---60232368058.pdfIn PDF document text
    • http://gurgaontaxi.com/pa/trainstation/uploads/image/file/69518821678.pdfIn PDF document text
    • https://vetamblj.si/ckfinder/userfiles/files/rodenazexebubelegotarumo.pdfIn PDF document text
    • http://exactblue.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613681b25b547---77756223204.pdfIn PDF document text
    • http://rockbond-aac.com/id-admin/fckImages/file/95173384703.pdfIn PDF document text
    • https://lsp.od.ua/wp-content/plugins/super-forms/uploads/php/files/720nlkq7j34ouoo2cnol7l3j63/92458855629.pdfIn PDF document text
    • https://lmcmanager.com/ckfinder/userfiles/files/95813333151.pdfIn PDF document text
    • https://beyondpins.com/calisma2/files/uploads/zotafexaxajonuzefon.pdfIn PDF document text
    • http://kepco-group.com/uploaded_files/userfiles/files/megibofadiniwutupese.pdfIn PDF document text
    • https://www.displaysdirectaustralia.com.au/application/third_party/ckfinder/userfiles/files/wasanixowewixexozesuvafum.pdfIn PDF document text
    • http://achilleferolla.it/userfiles/files/25127845547.pdfIn PDF document text
    • https://nakipoglugroup.com/upload/ckfinder/files/55920087852.pdfIn PDF document text
    • https://www.focus.mu/wp-content/plugins/super-forms/uploads/php/files/14c6d9b480378028cee880b49d155276/75464389572.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_off0000bc49.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBC49 10180 bytes
SHA-256: f58f68a8794830e082429f0b10ad75a644930ea5d1709d30184f8610211d640f
font_01_sfnt_off0000d325.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD325 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000eb37.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB37 17064 bytes
SHA-256: 56f6f7ca8f53bc0ad0b1ff130b3b0905fff3293a75614ed94c5f1b79cdd8d20f

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