Malicious PDF — malware analysis report

Static analysis result for SHA-256 8fc31ac879d90a87…

MALICIOUS

PDF

83.0 KB Created: 2021-09-14 03:38:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 38bc5a15c4eb563b74e560d27689c1a5 SHA-1: b2393086614090124387cb7faed253ec6dc30e56 SHA-256: 8fc31ac879d90a87a84f669e751de313a1367cce3bf2c79b23e127053d4ca604
156 Risk Score

Malware Insights

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

The PDF file contains numerous embedded URLs, many of which point to compromised websites or disposable hosting, indicating a link farm designed to redirect users. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware distribution. The presence of external URI links and compromised CMS upload links further supports this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 6

  • 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.
  • 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://irlanc.ru/uplcv?utm_term=score+hero+unlimited+money+apk
    • https://kamber.dk/wp-content/plugins/super-forms/uploads/php/files/dd45e6f299fc1c3bd885604dc33b5fb4/vilafitijeginesujife.pdf
    • https://arvikabc.com/images/uploadedimages/file/59264251084.pdf
    • http://arisutour.com/ckupload/files/volawosurax.pdf
    • https://fermuar.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134109cd88db---jafesepofosinuga.pdf
    • http://kapalishakti.com/ckfinder/userfiles/files/78779760316.pdf
    • https://pre-www.bridge-academy.com/uploaded/ckeditor/files/50175157888.pdf
    • http://perfect-gallery.com/userfiles/file/97163034936.pdf
    • https://yellowmangocafe.com/userfiles/file/19422335556.pdf
    • http://studioscoponi.eu/userfiles/files/40361447336.pdf
    • https://www.sibirprokat.ru/ckfinder/userfiles/files/xogawiloladelowabadezuzo.pdf
    • https://thisissati.com/userfiles/files/zakabezebugufarisobixi.pdf
    • http://www.mediagrand.hu/data/editorfile/43027495506.pdf
    • https://zakarpattya-tour.com/upload/31924403997.pdf
    • http://ewhamd.net/upFiles/ckeditor/files/xefugenavuduwere.pdf
    • http://vikingpaint.com/user_file/file/zakoxenalos.pdf
    • https://cupanghitam.com/contents/files/kilirugexovosizoxibogij.pdf
    • https://resortweeks.pro/userfiles/file/nodowezulumipe.pdf
    • https://thietkeweblongan.com/upload/files/siputunotesuj.pdf
    • http://avvocatoandreabruschi.it/userfiles/files/jakevew.pdf
    • http://lovepetclinics.com/file_media/file_image/file/81506579499.pdf
    • http://haohanlegend.com/Uploadfiles/files/zimizupi.pdf
    • http://aliancegroup.su/wp-content/plugins/formcraft/file-upload/server/content/files/1613f353c2de41---fodubovurosowufuk.pdf
    • https://www.hit-education.com/wp-content/plugins/super-forms/uploads/php/files/kfln6eb32evk09v5fpu332h8vb/luzeg.pdf
    • 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_off0000e013.bin
7a75ec82ee8f58d96bc40bd9442d6ec4224a77a19cea3d6c22ec5f3f8f155c01
pdf-font-stream PDF embedded font (sfnt) at offset 0xE013 10992 bytes
font_01_sfnt_off0000f969.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF969 16792 bytes
font_02_sfnt_off0001117b.bin
85f61942559055b157bb2f0b0cf8ff456d34815ee93793eb101d388aa55a7a3d
pdf-font-stream PDF embedded font (sfnt) at offset 0x1117B 17376 bytes