Malicious PDF — malware analysis report

Static analysis result for SHA-256 991e4fe28d9739d9…

MALICIOUS

PDF

81.5 KB Created: 2021-08-15 00:53:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 21496fd27b7bb7eea338a6fc9c096bc1 SHA-1: 38df47458216bebbe73b09aa3384cd8b99f989f3 SHA-256: 991e4fe28d9739d964bdcb4e506af128349e6d8b91c32ad0ee06bd7274f53d8f
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and a significant number of external URIs, many of which point to compromised CMS uploads or are part of a link farm hosted on disposable domains. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware distribution through these linked resources.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://kfbi.ru/content/file/goseraxo.pdf
    • https://k-kompany.ru/wp-content/plugins/super-forms/uploads/php/files/013703cfd4a345ddbead4eed948dfaeb/28014870070.pdf
    • https://www.dazzlingdecor.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16075452a40f8d---6953347458.pdf
    • https://konferencii.ru/js/ckfinder/userfiles/files/ruzisinomijefoxar.pdf
    • https://cuisinescartier.ca/upload/editor/file/16937565507.pdf
    • http://nhhs78.org/clients/63854/File/70436574763.pdf
    • http://lideparts.com/userfiles/file/1620612759.pdf
    • https://zemiigori.com/uploads/file/57846072776.pdf
    • https://estidevelopers.com/wp-content/plugins/super-forms/uploads/php/files/65c30f488b8f3fba973c2b719087690d/49600319870.pdf
    • http://exactblue.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609f4f8ed6b58---48405980177.pdf
    • http://luckyassessoria.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160ae503880ad2---mugerorita.pdf
    • http://www.tif.cn/wp-content/plugins/super-forms/uploads/php/files/1qbug0gv5lpanruunm1teeq53j/81475174607.pdf
    • https://sabagdasarov.ru/upload/file/60936710396.pdf
    • https://unosms.us/userfiles/file/91587540706.pdf
    • http://lustigersteirer.at/userfiles/file/55081658487.pdf
    • https://njsolarpower.com/wp-content/plugins/super-forms/uploads/php/files/e7c9d310b5c5db226cf8a82221be05f4/nuwarilepesaboxup.pdf
    • https://jamisonfurnace.ca/userfiles/files/49824084635.pdf
    • http://nyett.hk/uploads/news/files/52215481323.pdf
    • https://triosms.com/userfiles/file/76875612088.pdf
    • http://pcserviszlin.cz/ckfinder/userfiles/files/xobuwafuvuralu.pdf
    • https://brune-schmuckwerk.de/ckfinder/userfiles/files/dekuraro.pdf
    • http://1544-7419.net/upload/fckeditor/file/85456664294.pdf
    • https://advancedbusiness.co/wp-content/plugins/super-forms/uploads/php/files/ef0d4bb97b9516a6ebe582254793b73e/xakibamumolun.pdf
    • http://muaah.ca/userfiles/files/35012232175.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BvfzZFkJO3s/uplcv?utm_term=how+to+calculate+power+transformer+size
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000db75.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xDB75 16792 bytes
font_01_sfnt_off0000f387.bin
e0bea1297b91ba18bb82f282b9766cc14d5c4eaced131d0c8f2d0a5ea2918424
pdf-font-stream PDF embedded font (sfnt) at offset 0xF387 16708 bytes
font_02_sfnt_off00011ed1.bin
0f306363459f7a32352a3e5524477d88ef4f9300ccf314992213af4c2875d0db
pdf-font-stream PDF embedded font (sfnt) at offset 0x11ED1 10876 bytes