Malicious PDF — malware analysis report

Static analysis result for SHA-256 31311e267f39d96d…

MALICIOUS

PDF

70.0 KB Created: 2021-09-19 07:34:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: d391bd11d39076f4e37943e0c08cad6d SHA-1: 7ed23ff422c786bc2041296dffa13cb6d0e36ef2 SHA-256: 31311e267f39d96d3512f565d0e6ae7f10e18b7f9237222f2e4e9056d9fa46b9
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was flagged as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. The document contains numerous links, many pointing to disposable hosting or compromised CMS uploads, suggesting it functions as a link farm designed to redirect users to malicious sites. The presence of PDF-specific heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' further supports this attack pattern. No scripts were extracted, but the overall structure and URL distribution point towards a phishing or malware distribution lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9893

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://laborke.ru/uplcv?utm_term=clean+master+app+download+old+version PDF link annotation
    • http://www.sauminandy.com/fckimages/file/39809983556.pdfIn PDF document text
    • http://vinaaquachem.com/uploads/files/xebobaxogu.pdfIn PDF document text
    • http://moonlightmontessori.com/upload/files/7807510755.pdfIn PDF document text
    • https://ww150003.linebot.net/upfile/files/20210909105325.pdfIn PDF document text
    • https://jbdclothiers.net/emailer/userfiles/file/degigapefab.pdfIn PDF document text
    • http://melly-incendie.fr/img_db/malurokasu.pdfIn PDF document text
    • https://plantbiochem.com/ckfinder/userfiles/files/40420259111.pdfIn PDF document text
    • http://huucodatlanh.com/userfiles/file/xijeruzesarumufume.pdfIn PDF document text
    • http://albino-pitti.com/pub_img/file/40999070393.pdfIn PDF document text
    • https://onutglen.com/caningest/images/file/25203235663.pdfIn PDF document text
    • http://bdnchem.com/upload/files/rutejomuvuterogudib.pdfIn PDF document text
    • http://www.cavice.fi/tiedostot/files/28348877247.pdfIn PDF document text
    • http://meghdoothsuzuki.com/uploads/pogabufivapibikasujel.pdfIn PDF document text
    • http://nhadephoanhao.vn/upload/ckupload/files/7358686751.pdfIn PDF document text
    • https://nicemexico.net/wp-content/plugins/formcraft/file-upload/server/content/files/16146773269527---wolopipabakigigi.pdfIn PDF document text
    • http://tw-tms.com/uploadpic/xw/files/50104561768.pdfIn PDF document text
    • http://captaincook.hu/userfiles/file/89953945463.pdfIn PDF document text
    • https://www.energetisch-therapeut-estie.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1612ea078ac4a7---zovelitagigizesolukonev.pdfIn PDF document text
    • http://plise.org/userfiles/file/jilapinaf.pdfIn PDF document text
    • https://baatco.com/ckfinder/userfiles/files/wigaw.pdfIn PDF document text
    • https://okazdedziecko.pl/_files/Media/file/77403846095.pdfIn PDF document text
    • https://deewo.de/wp-content/plugins/formcraft/file-upload/server/content/files/161461ade1f121---jigaguxitalijeroviwurefa.pdfIn PDF document text
    • https://ruiguoex.com/upfile/files/2021/09/14/75966558604.pdfIn PDF document text
    • http://aptekadc.pl/userfiles/userfile/79263611989.pdfIn PDF document text
    • http://tomaszfilipczak.pl/userfiles/file/vogowutuwudajitonedaw.pdfIn PDF document text
    • http://ks-system.co.uk/ckfinder/userfiles/files/93509601123.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_off0000b3be.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB3BE 15144 bytes
SHA-256: 610832e287b8a84dc5bfcf3b4ea2065ae4815c409266734fe9a4c77c1fafebf5
font_01_sfnt_off0000d9b4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9B4 10736 bytes
SHA-256: c041162c5f4e091b69c6c6844822b744a82244bbad227ed013ea7e25cd1338d9
font_02_sfnt_off0000f265.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF265 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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