Malicious PDF — malware analysis report

Static analysis result for SHA-256 83f91db89be7d96a…

MALICIOUS

PDF

80.3 KB Created: 2021-09-23 15:57:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: 0a1993ae4de744e87679517f727016e9 SHA-1: bfd310c4372ca2ebd28b264489909c0dcb5c91ac SHA-256: 83f91db89be7d96ae2d3a764c5f24411b6675432ef8829ace70cf9afdd01aea0
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded URLs, many of which point to disposable hosting or compromised CMS upload directories, indicative of a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery. The presence of external URIs and link farm heuristics points towards an attempt to redirect the user to a malicious site.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

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 https://catamma.ru/uplcv?utm_term=wps+office+old+version+for+android PDF link annotation
    • http://nova-auto.com/upload/37774792402.pdfIn PDF document text
    • https://tecsal.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161359d488fbca---xugowu.pdfIn PDF document text
    • http://marcth.pl/media/fck/file/29284376892.pdfIn PDF document text
    • http://0851gay.org/userfiles/202109file/2021092319594170554.pdfIn PDF document text
    • http://cokhivietuc.webthoidai.com/img-vietuc/files/34485524471.pdfIn PDF document text
    • http://www.cddfct.com/up_files/file/27174027350.pdfIn PDF document text
    • http://tomgiongvip.com/uploads/files/file/begusaj.pdfIn PDF document text
    • http://ontis.sk/editor_uploads/system/files/97506760610.pdfIn PDF document text
    • http://lalitas-thaimassage-spa.de/wp-content/plugins/formcraft/file-upload/server/content/files/16133322a61b39---56214123605.pdfIn PDF document text
    • http://xn--80aafkatcapceshpicpg3h.xn--p1ai/pict/file/12367263199.pdfIn PDF document text
    • https://t4g.nasscomfoundation.org/wp-content/plugins/super-forms/uploads/php/files/bruut6mfho77qiohc12ki7r025/84940583393.pdfIn PDF document text
    • http://www.ruben.pl/ckfinder/userfiles/files/79229494596.pdfIn PDF document text
    • http://victorylimo1.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e331b9bc31---xixowevo.pdfIn PDF document text
    • https://xn--78-6kce7dfhb9dwb.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/e8c7256676549ffbb1d5ffb4860e4c1b/68742112049.pdfIn PDF document text
    • https://jackinthegymtpe.com/uploads/files/202109091702516756.pdfIn PDF document text
    • https://giraffeng.net/infodaily/gen-ckfinder/userfiles/files/rufejo.pdfIn PDF document text
    • http://mateuszkucharski.pl/admin/file/fupobukifimezulale.pdfIn PDF document text
    • https://senzedigicraft.com/wp-content/plugins/super-forms/uploads/php/files/5003a9899f0002986a076a87dad76f5a/47214485609.pdfIn PDF document text
    • https://megalightgroup.lv/uploads/files/lonezuvaduniwivut.pdfIn PDF document text
    • https://noukos.gr/wp-content/plugins/formcraft/file-upload/server/content/files/16133cdaaf2d2b---17631024718.pdfIn PDF document text
    • http://xn--80aesyq.xn--p1acf/files/file/jadixababupelatibetew.pdfIn PDF document text
    • http://veganogle.es/uploads/ckfinder/files/58939275179.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_off0000d020.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD020 20192 bytes
SHA-256: 98fd382727fffcc84bc97473741299155871d0d3cb95c348b0a8446d87fc1873
font_01_sfnt_off000103f4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103F4 10576 bytes
SHA-256: 722afbd487f8d4c901a97423b15ffc47bc1a11b7ed574397bc0c3179c7e9c4c9
font_02_sfnt_off00011c39.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C39 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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