Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb8350fa24dbcace…

MALICIOUS

PDF

80.1 KB Created: 2021-09-09 15:57:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: f36aa120161221bfc4879cd9946760eb SHA-1: a6f99630a1be91e9fc86be46cc4d6af0a95ca73b SHA-256: cb8350fa24dbcace9b7c0e258b86d1e26aafe05d15ec17f406192de1e0831e05
156 Risk Score

Malware Insights

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

The PDF contains a large number of links pointing to various domains, many of which appear to be compromised or disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or distributing further malware. The document body is heavily obfuscated and unreadable, providing no direct user-facing content, but the heuristic firings confirm the presence of a link farm.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

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 http://csc0532.com/userfiles/file/20210903215235_kmhig4.pdf In PDF document text
    • https://villadorottya.hu/uploads/frontend/files/22704752046.pdfIn PDF document text
    • https://xtremefitksa.com/ckfinder/userfiles/files/28667025115.pdfIn PDF document text
    • http://enjoy.sk/editor_uploads/system/files/95229890123.pdfIn PDF document text
    • http://fujiya-burbank.com/uploads/files/24766870756.pdfIn PDF document text
    • http://rickgrisolia.com/userfiles/files/linizezelesosidofinojasog.pdfIn PDF document text
    • http://orthodoxnews.us/file/28620645424.pdfIn PDF document text
    • http://www.kowel.com/ckfinder/userfiles/files/1630923400.pdfIn PDF document text
    • http://domexpo.ru/up/file/fovafugatilomitebaf.pdfIn PDF document text
    • https://fonixkoncert.hu/upload/file/nosubofafopisu.pdfIn PDF document text
    • http://nnk.gr/wp-content/plugins/formcraft/file-upload/server/content/files/16137b546e63d1---9512366869.pdfIn PDF document text
    • https://chongtham68.com/app/webroot/uploads/files/83254891717.pdfIn PDF document text
    • https://www.novet.de/wp-content/plugins/formcraft/file-upload/server/content/files/161335c8e702be---lawiposaxofasudanagebo.pdfIn PDF document text
    • https://wic-net.com/userfiles/file/88556180181.pdfIn PDF document text
    • http://www.logistiekverbeteren.nl/ckfinder/userfiles/files/40020441481.pdfIn PDF document text
    • http://cserepakcio.hu/xdata/file/pumugikirejumoguvezo.pdfIn PDF document text
    • https://cbconsulting112.ca/userfiles/files/95433386022.pdfIn PDF document text
    • https://www.carlosfunes.es/wp-content/plugins/formcraft/file-upload/server/content/files/1613959fea663c---bimupigape.pdfIn PDF document text
    • https://wamsconference.com/wp-content/plugins/super-forms/uploads/php/files/c9b1bc0603b47ebfb48984142cdaa4e2/44867863515.pdfIn PDF document text
    • http://arisutour.com/ckupload/files/vofarowatigaju.pdfIn PDF document text
    • https://pakianco.ir/data/image/uploads/news/files/nifizebimesodawi.pdfIn PDF document text
    • http://telegid.tv/userfiles/files/tukitiratilanobewopubi.pdfIn PDF document text
    • http://nawoo.net/userData/board/file/5169575813.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/cv9VXjIrmdE/uplcv?utm_term=how+to+boost+cpu+performance+androidPDF 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_off0000d41d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD41D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ec2f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC2F 17516 bytes
SHA-256: f72535214fb98d5f193022cf1ec8db682187f41ec2cec169ca039c386291a166
font_02_sfnt_off0001195e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1195E 11052 bytes
SHA-256: 4e0ef3dd04fc4c6ac3107d3cebbe34372346ead7c858216a006516ad086e1280