Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef538607c11c3c51…

MALICIOUS

PDF

88.9 KB Created: 2021-09-13 00:57:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: dc6fac00d50728be66ad543ac0f4ae50 SHA-1: 719e716b59e7f3804830aa9b633ee8e0b6ed78b1 SHA-256: ef538607c11c3c51d7cb02a5c0938996160ccdf8ab2d1205bac1525c9e524a5d
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to external websites, many of which are hosted on compromised CMS platforms or disposable hosting, suggesting a link farm for phishing or malware distribution. The ML classifier and ClamAV detection strongly indicate malicious intent. Although no scripts were explicitly extracted, the heuristic firings related to link farms and compromised uploads point towards a phishing or malware delivery scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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://archism.ru/uplcv?utm_term=pdf+editor+watermark+remover+online PDF link annotation
    • https://retentionstudentexperience.com/wp-content/plugins/formcraft/file-upload/server/content/files/161345d3ce3d4f---papaxodipaf.pdfIn PDF document text
    • http://www.homefacelifters.com/wp-content/plugins/super-forms/uploads/php/files/e75d45ffd5efcfc02181c5a830292530/woxedepixalarinugu.pdfIn PDF document text
    • http://driver-jazda.pl/upload/file/48142777925.pdfIn PDF document text
    • http://popnmusic.fr/userfiles/file/87941233336.pdfIn PDF document text
    • http://banquat.com/userfiles/files/zovuradololup.pdfIn PDF document text
    • http://onestep-tokyo.com/userfiles/file/zomajaxuxeta.pdfIn PDF document text
    • https://xeroxexpres.cz/userfiles/file/zepisavoselafekolu.pdfIn PDF document text
    • https://kirbas.com/img/uploaded/file/97856025606.pdfIn PDF document text
    • http://le383.com/uploads/files/vididabebipagasatalupi.pdfIn PDF document text
    • http://podiummoda.ru/userfiles/file/26248679679.pdfIn PDF document text
    • http://claudiamelchior.it/images/file/pamekuzeto.pdfIn PDF document text
    • http://5percent-design-action.com/upload/users/files/lupikibokel.pdfIn PDF document text
    • https://fallsplat.se/bildbank/file/rudosotuso.pdfIn PDF document text
    • http://swhwsolution.it/ckeditor-ckfinder-integration/uploads/files/fasutekinimiruzojokurozo.pdfIn PDF document text
    • http://gajagotour.com/UserFiles/file/kolelikup.pdfIn PDF document text
    • http://knupress.com/pds/editor/file/39738274701.pdfIn PDF document text
    • http://tecniagua.es/uploads/ckfinder/files/64648601044.pdfIn PDF document text
    • http://longthinhphat.net/uploads/files/92400664364.pdfIn PDF document text
    • http://bzws.zhanyougame.com/ckfinder/userfiles/files/zajakufoko.pdfIn PDF document text
    • http://www.kevinbrooks.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1613e67eb7fcb9---91626846142.pdfIn PDF document text
    • http://gapp.fr/medias/files/82052059576.pdfIn PDF document text
    • http://locnuocvietmy.com/Images_upload/files/98793722560.pdfIn PDF document text
    • https://seeandhearbetter.ie/img/shop/contents/timumunabimuvidoxapiw.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_off0000f14f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF14F 10592 bytes
SHA-256: 4e2cfeaac04bad0e23adcc4f3ee2c0515e53fd8d81aa95e400ce82cd7654fb73
font_01_sfnt_off0001098a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1098A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001219c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1219C 19772 bytes
SHA-256: d800f4e2448a0fc931445218ac6f904337c89364325a1413851755ee04dcae5c