Malicious PDF — malware analysis report

Static analysis result for SHA-256 8a51b88e3643020f…

MALICIOUS

PDF

73.0 KB Created: 2021-09-28 04:14:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-02
MD5: 25e3b515749e0c877eab8cb7999530b5 SHA-1: 117623969a02331744cab90e862da292b7888de2 SHA-256: 8a51b88e3643020f85434aeac59987764faa016f03b8fb48b946bde8fb1ec2e8
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a large number of external links, many of which point to other PDF files hosted on potentially compromised websites. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The presence of numerous links to disposable hosting and compromised CMS upload directories suggests a tactic to obscure the ultimate destination and evade detection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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 https://krisoc.ru/uplcv?utm_term=gomovies+online+watch PDF link annotation
    • http://centronegozi.com/public/41709390162.pdfIn PDF document text
    • http://dangkyidol.com/wp-content/plugins/super-forms/uploads/php/files/n2ktcphtv2gip670pu1bmiqvii/borofowetegetudu.pdfIn PDF document text
    • http://csa.china-led.net/static/editor/ckeditor/ckfinder/upfile/files/5873932457.pdfIn PDF document text
    • http://meyergarden.com/ckfinder/userfiles/files/23203724018.pdfIn PDF document text
    • http://tz5168.com/uploadfile/image/2021/09/26/file/20210926_192513_198.pdfIn PDF document text
    • http://pecsimutargygaleria.hu/files/file/sixemaniv.pdfIn PDF document text
    • http://devveb.net/userfiles/file/79924717371.pdfIn PDF document text
    • https://www.tifdip.com/wp-content/plugins/formcraft/file-upload/server/content/files/16152326e92293---jinufidupavokomakima.pdfIn PDF document text
    • http://sirindhorn.net/upload/File/wonadufub.pdfIn PDF document text
    • http://mopi.eu/ckfinder/userfiles/files/patobatekaxuri.pdfIn PDF document text
    • https://pre-www.bridge-academy.com/uploaded/ckeditor/files/11576158912.pdfIn PDF document text
    • http://n3ss.ro/ckfinder/userfiles/files/41994830239.pdfIn PDF document text
    • https://ver9.sonikgps.com/ckfinder/userfiles/files/27096918892.pdfIn PDF document text
    • http://odontotecnicacoop.it/userfiles/file/36543860861.pdfIn PDF document text
    • http://www.argentum.com/wp-content/plugins/super-forms/uploads/php/files/ibr8ponj2a40th8j7ib386uouo/47269977900.pdfIn PDF document text
    • http://qboardapp.com/wp-content/plugins/super-forms/uploads/php/files/89f93b7fde0dce33f1f739edbd38217e/keked.pdfIn PDF document text
    • https://inclinedigital.com/wp-content/plugins/formcraft/file-upload/server/content/files/16144e523a70b8---gexomopudaj.pdfIn PDF document text
    • http://freetds.net/userfiles/file/60174092699.pdfIn PDF document text
    • http://vijyaiprismcrm.com/userfiles/files/xajafalubakotosovodukuf.pdfIn PDF document text
    • http://bertrandetgastineaudesigners.fr/userfiles/file/95288993752.pdfIn PDF document text
    • https://aradovan.com/userfiles/file/wolopataxazabirivin.pdfIn PDF document text
    • https://portecitadelle.portecitadelle.ca/ckfinder/userfiles/files/zemosuludenepamivogoj.pdfIn PDF document text
    • http://www.myhhsi.com/wp-content/plugins/super-forms/uploads/php/files/02c36a6410350689ac7c327bd4481329/xiburubu.pdfIn PDF document text
    • https://www.vita-organic.eu/admin/ckfinder/userfiles/files/pemipaporibigizume.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_off0000b7d5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB7D5 18224 bytes
SHA-256: bb8944b1a0592f0c64e806857672e69b5935311f4b721a34a9a85d79b960d4e1
font_01_sfnt_off0000e6b4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6B4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fecb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFECB 10588 bytes
SHA-256: 0fd6a491e91466a0b72e0fe63135a6f47b83a75c29cacc481d086f86e2b2a733