Malicious PDF — malware analysis report

Static analysis result for SHA-256 23317d420934b781…

MALICIOUS

PDF

79.8 KB Created: 2021-09-22 16:43:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 9d33771ac527d782ce4ef627fe2e18ee SHA-1: 00cf3f7dc2a8889e658a93a48a9a2e5189b68c53 SHA-256: 23317d420934b781206809f6b103f772f3fd2ebdb4db6c3edf27b30f986e580b
66 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document was flagged by an ML classifier as malicious. It contains numerous embedded URLs, with the heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicating a high number of distinct hosts and links, suggesting a link farm designed to redirect users. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, which is not inherently malicious but can be used to construct malicious PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9949

Heuristics 4

  • 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://retailpark.bg/uploads/wysiwyg/files/37349917560.pdf In PDF document text
    • https://dsodrecital.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613cc442e3f27---62605337217.pdfIn PDF document text
    • http://uitvaartverzorgingsindex.nl/images/uploads/41005631311.pdfIn PDF document text
    • http://cheapneasytrafficschool.com/CheapNEasyTrafficSchool/pa/trainstation/uploads/image/file/42252145691.pdfIn PDF document text
    • http://safeabortionnepal.com/userfiles/file/xusebiluvonoxizuwafokip.pdfIn PDF document text
    • http://psystems.gr/Administrator/uploads/userpics/OutPostImages/files/60940939839.pdfIn PDF document text
    • https://noriupapildu.lt/ckfinder/userfiles/files/jivuzesi.pdfIn PDF document text
    • http://delfosventures.eu/userfiles/files/wevuxodafegosipu.pdfIn PDF document text
    • http://dulichtantai.com/files/uploaded/files/99279463914.pdfIn PDF document text
    • https://cryptobasics.biz/uploads/files/kasuliloxage.pdfIn PDF document text
    • https://amt-alarmy.pl/userfiles/file/vutikudos.pdfIn PDF document text
    • http://pbpharm.com/upload/files/57970022860.pdfIn PDF document text
    • http://evola.it/userfiles/files/99524366792.pdfIn PDF document text
    • http://pogotowienaukowe.com/Upload/file/45807369125.pdfIn PDF document text
    • http://delfosventures.net/userfiles/files/73667697232.pdfIn PDF document text
    • http://ailizia.com/userfiles/datepozirazufudaw.pdfIn PDF document text
    • http://pmke.cz/pictures/files/4513995631.pdfIn PDF document text
    • http://i-harmonics.com/upload/files/33385176656.pdfIn PDF document text
    • http://tungalag.mn/userfiles/files/bimonosazidigexujan.pdfIn PDF document text
    • http://rafaelstore.ru/upload/files/videsoseturalitip.pdfIn PDF document text
    • https://burgas-remonti.com/userfiles/file/66225569320.pdfIn PDF document text
    • http://citra.cl/userfiles/file/ponuzukekaz.pdfIn PDF document text
    • https://semagro-msw.ru/pics/images/file/voleku.pdfIn PDF document text
    • https://pavaniautismschools.com/wp-content/plugins/super-forms/uploads/php/files/k828d9ph9taiioo10q7u3ffqnt/wubalopewetuzamokom.pdfIn PDF document text
    • http://mitchelllawoffice.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/3516148519.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1xuhb7AK25c/uplcv?utm_term=guitar+hero+online+unblockedPDF 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_off0000d1b1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD1B1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e9c8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE9C8 10668 bytes
SHA-256: c15acb89fc7b2b8e43d15a8b7f02925c39101288b8966db51e503be0928db4e5
font_02_sfnt_off0001021e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1021E 18096 bytes
SHA-256: e1afb05c99c48f10dfa58c9cf7646a089ca3166f98ea8e4516b38f2f94c867a1