Malicious PDF — malware analysis report

Static analysis result for SHA-256 dfef89852bc2f1cd…

MALICIOUS

PDF

67.5 KB Created: 2021-09-26 08:13:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 67ef310457c36e183e32f3c1c35d9593 SHA-1: 1857d6e766e214f0b59c4cc7d2324b24e8caa69d SHA-256: dfef89852bc2f1cd05524d48ae2d85330678bd0630b3711707bf842b209ca42b
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by ClamAV and an ML classifier, with heuristics indicating embedded JavaScript and a link farm pointing to compromised CMS uploads. The embedded JavaScript likely serves to download and execute a second-stage payload, while the numerous external links suggest a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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://krisoc.ru/uplcv?utm_term=android+profile+app PDF link annotation
    • http://seoulgreeter.com/userData/board/file/83406422589.pdfIn PDF document text
    • http://ukrfirework.com/images/file/20272270140.pdfIn PDF document text
    • http://upservice.expert/admin/ckfinder/userfiles/files/zoxurokowawesivu.pdfIn PDF document text
    • http://nikolalepojevic5.com/multimedia/file/wapasatigitefejejoxodifo.pdfIn PDF document text
    • http://radecznica.pl/userfiles/file/85577450437.pdfIn PDF document text
    • https://www.totalblissbeauty.com.au/application/third_party/ckfinder/userfiles/files/rigelewuvamonarigi.pdfIn PDF document text
    • https://himalayanespresso.com/espresso_ckfinder/userfiles/files/rusuvuxewesil.pdfIn PDF document text
    • http://prplus4u.com/ckupload/files/2167888333.pdfIn PDF document text
    • https://pbpkrosno.com/fckfile/720766770.pdfIn PDF document text
    • http://dossalas.com/wp-content/plugins/super-forms/uploads/php/files/fcd2ecfecfa1a101dfe2ddbe5146d70b/38637418481.pdfIn PDF document text
    • http://cabinet-blin.fr/ressource/site-image/files/zuwugosulibirijus.pdfIn PDF document text
    • http://danieldesignpro.com/userfiles/zidutojanigosixinumijivo.pdfIn PDF document text
    • http://chokysitohang.com/Uploads/userfiles/files/16941833679.pdfIn PDF document text
    • http://rosritual.su/app/webroot/js/ckfinder/userfiles/files/89803149234.pdfIn PDF document text
    • http://banglatalkies.com/dynamic-images/cms/file/75640830903.pdfIn PDF document text
    • https://bruceautoservice.com/files/file/51080507984.pdfIn PDF document text
    • https://divorcioconsensual.com.br/wp-content/plugins/super-forms/uploads/php/files/9f6d5571da93f896508c5ba2b64f564c/46066396120.pdfIn PDF document text
    • https://www.vpn-solutions.com.pe/ckfinder/userfiles/files/pilunuxud.pdfIn PDF document text
    • http://indyztyle.com/ckfinder/userfiles/files/93140527147.pdfIn PDF document text
    • http://www.maoles.com/wp-content/plugins/formcraft/file-upload/server/content/files/16147347c7aa46---ximovufaxapimobaf.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_off0000ab9e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAB9E 15388 bytes
SHA-256: 7a7feb49b591512b80c20031e86befa1c452ca0ca12b2edf3d8afae328dadab7
font_01_sfnt_off0000d21e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD21E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000ea35.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA35 10204 bytes
SHA-256: f509572279c908ce8a3d2faa3d51cec19ab0dcc0b9ad55a6b6618923876dab18