Malicious PDF — malware analysis report

Static analysis result for SHA-256 55f5eb268e1c7557…

MALICIOUS

PDF

68.1 KB Created: 2021-09-16 03:20:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 462af24205d783b785c03094cf6e9dde SHA-1: 9303dd3cdda2ed8d2c4acd1cfe7ade665deed760 SHA-256: 55f5eb268e1c755795f6f9c001b5052bc042282457350f725c4824ad97595ca8
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, many of which are algorithmically generated and hosted on disposable domains, indicating a link farm designed to distribute malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware delivery. Although no scripts were explicitly extracted, the PDF structure and heuristic firings point towards the exploitation of PDF vulnerabilities or social engineering to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9966

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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://inwebjor.ru/uplcv?utm_term=7th+maths+book PDF link annotation
    • https://nocnepal.org.np/ckfinder/userfiles/files/21478366569.pdfIn PDF document text
    • http://ipsgroupjjn.org/userfiles/file/golobu.pdfIn PDF document text
    • https://stthomasorthodoxchurchsouthpampady.com/userfiles/file/19279501948.pdfIn PDF document text
    • https://borgopitti.it/userfiles/file/narojikunosizalinemawu.pdfIn PDF document text
    • https://mbamantra.com/ci/userfiles/files/85549870738.pdfIn PDF document text
    • https://formapolis.it/wp-content/plugins/super-forms/uploads/php/files/1ae0c4de90395e80adca954ef062be83/nubulufidosilagaj.pdfIn PDF document text
    • http://pomelieagency.com/userfiles/files/vufeximomor.pdfIn PDF document text
    • http://chemonova.com/FCKeditor/file/diwodasuxesujana.pdfIn PDF document text
    • http://mwflower.com/upimagesfile///45337331772.pdfIn PDF document text
    • https://damiel.eu/userfiles/file/33193920524.pdfIn PDF document text
    • http://melabo.com/upload/files/94861913480.pdfIn PDF document text
    • http://gptools.net/userfiles/file/piluvelalusasikikaluz.pdfIn PDF document text
    • http://kool-house.com/upload/editor/file/zivakepogujowusa.pdfIn PDF document text
    • http://speckletrack.com/update/editor/file/96350140106.pdfIn PDF document text
    • http://dentistturkey.com/image/files/pobulozag.pdfIn PDF document text
    • https://indicaperu.com/userfiles/file/39331196843.pdfIn PDF document text
    • http://www.prieteniitehnicii.ro/documente/file/jomiwogiziji.pdfIn PDF document text
    • https://easternresources.net/ckfinder/userfiles/files/44375894435.pdfIn PDF document text
    • http://nessium.net/userfiles/file/dezoxuvile.pdfIn PDF document text
    • https://mercedesmazo.es/wp-content/plugins/formcraft/file-upload/server/content/files/1614285e9ab322---54170080422.pdfIn PDF document text
    • http://studiopiergentili.it/userfiles/files/vanatotezipej.pdfIn PDF document text
    • http://93564497.com/userfiles/52338816329.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_off0000adf1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xADF1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c608.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC608 10084 bytes
SHA-256: 794191ac184a4e3c873f4f2fb82064e2769d641df8f9b03a1884dcacacd0bfe8
font_02_sfnt_off0000dc94.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC94 15568 bytes
SHA-256: 952cb5aed4ae34fee0bf18e698558fdf9e7e2ae6248f5734dcf14f427d86bb4e