Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4535a2a19681b56…

MALICIOUS

PDF

67.9 KB Created: 2021-09-25 15:06:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-02
MD5: 0c4338539dd3f504ba0bd193254bad7d SHA-1: a2420d7585ca19ea4b0a4ca133cdc650d015384a SHA-256: a4535a2a19681b56e97bf1fc68e5ad425801675916acf9db92c68a3060bc23aa
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing embedded JavaScript and a large number of external links. Several heuristics indicate that these links point to compromised CMS upload storage and disposable hosting, suggesting a link farm designed for phishing or malware distribution. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or redirecting users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9966

Heuristics 7

  • 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.
  • 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 https://crewmak.ru/uplcv?utm_term=watch+reality+tv+shows+online+free PDF link annotation
    • https://observatoire-omic.org/documents/file/34913318838.pdfIn PDF document text
    • https://bluetact.com/ckfinder/userfiles/files/lizububagatujodek.pdfIn PDF document text
    • http://elesud.it/img_pagine/file/darivevolevegu.pdfIn PDF document text
    • http://tuning-zone.eu/userfiles/file/zazujipu.pdfIn PDF document text
    • https://www.abrasco.org.br/ckfinder/userfiles/files/75312390509.pdfIn PDF document text
    • https://repetitorebi.ge/userfiles/files/farodasobilozigalive.pdfIn PDF document text
    • http://bbfrontedelmare.com/userfiles/files/ketalasusadunidofoziwisiw.pdfIn PDF document text
    • http://qdjshg.com/files/file/79444308330.pdfIn PDF document text
    • http://www.hon-ro.hu/userfiles/files/93690390026.pdfIn PDF document text
    • http://3bbb.fr/ckeditor/upload/files/moperozadogexadixid.pdfIn PDF document text
    • http://indigobaby.eu/upload/files/ravaxegoruzajudibapul.pdfIn PDF document text
    • http://www.cemeba.com/uploads/ckfinder/files/tarokebomalolivaxuso.pdfIn PDF document text
    • http://erulingua.hu/uploads/content_files/files/5554358802.pdfIn PDF document text
    • http://modulobase.com/userfiles/file/27106655800.pdfIn PDF document text
    • https://jmtours.co/aym_image/files/womaravudadewatogemi.pdfIn PDF document text
    • http://machi-tomo.xyz/js/ckfinder/userfiles/files/79585617042.pdfIn PDF document text
    • http://www.alfainstal.pl/wp-content/plugins/formcraft/file-upload/server/content/files/16147c5e775ec0---53643029100.pdfIn PDF document text
    • https://espritgt.com/userfiles/file/20627807153.pdfIn PDF document text
    • http://www.og2c.com/images/file/vagojederosabit.pdfIn PDF document text
    • http://www.specemc.ru/upload/files/56264144494.pdfIn PDF document text
    • http://jamoncup.es/wp-content/plugins/formcraft/file-upload/server/content/files/1614612a290e21---5680798986.pdfIn PDF document text
    • http://www.ashtralmedia.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130ca1d34b06---tufisazuzokomowedibizevu.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_off0000ad5d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAD5D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c574.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC574 10692 bytes
SHA-256: 9e4eb080812309148a9621d6873d342fe0c8bdc048f0342e9b0be622e0c0b15c
font_02_sfnt_off0000de06.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE06 14552 bytes
SHA-256: 270240dcf06be21b228b7e43e530612a71a849d7f3890273d950f8ce95256bdf