Malicious PDF — malware analysis report

Static analysis result for SHA-256 c166c594722f0373…

MALICIOUS

PDF

90.4 KB Created: 2021-09-20 13:22:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: cbc7bfabb2d89d662a0be9ca9d82f89c SHA-1: 9e2870def39656a4d8741c032a13bf8fa7d9b072 SHA-256: c166c594722f0373c92427d2bd68d96d14660dbd8f00ab20e6430f0af926fd2c
176 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and an ML classifier, with heuristics indicating a malformed exploit stream and a link farm pointing to compromised CMS uploads. The PDF contains numerous embedded URLs, many of which are hosted on disposable domains or compromised WordPress sites, suggesting a phishing or malware distribution campaign. Although no scripts were explicitly extracted, the PDF structure and embedded URIs strongly suggest an attempt to redirect the user to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9923

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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=android+ftp+server+external+sd+card PDF link annotation
    • https://ag-concept.ru/wp-content/plugins/super-forms/uploads/php/files/d739c9a2d02bcad7554c4fc02909bc24/golababudemexumeleserewu.pdfIn PDF document text
    • https://snapstudios.ca/userfiles/file/59222738328.pdfIn PDF document text
    • http://www.likoda.com.tw/upload/ckimg/files/84881545665.pdfIn PDF document text
    • http://gyndoktors.de/ckfinder/userfiles/files/suketevoruxuvowudo.pdfIn PDF document text
    • https://pierrelemagicien.com/userfiles/file/nazuretuguwurak.pdfIn PDF document text
    • http://juditphotography.com/picture/userfiles/file/13339516818.pdfIn PDF document text
    • https://preprodpcb.com/userfiles/files/42161067601.pdfIn PDF document text
    • https://nguyenvanhuongloc.vn/app/webroot/files/images/pages/files/41396198610.pdfIn PDF document text
    • http://1night2day.com/ckupload/files/sejokireduvos.pdfIn PDF document text
    • http://www.iciparis.ru/ckfinder/userfiles/files/sanaxol.pdfIn PDF document text
    • http://rainternacional.com/userfiles/file/97240729597.pdfIn PDF document text
    • http://izhar-energy.com/userfiles/file/2511217826.pdfIn PDF document text
    • http://barrybusiness-crm.com/ressource/devis-photo/files/11596187621.pdfIn PDF document text
    • http://andreevmag.com/wp-content/plugins/super-forms/uploads/php/files/073f197ea495080d1e991390871886bb/80456333639.pdfIn PDF document text
    • http://www.jindatunnel.com/up_files/file/getovudovajo.pdfIn PDF document text
    • http://psn-monolit.ru/img_file/files/lotabapukizebapete.pdfIn PDF document text
    • http://toptoptraining.ru/img/upload/file/bilul.pdfIn PDF document text
    • http://fishngrill.iorderfoods.com/uploads/files/19606364422.pdfIn PDF document text
    • https://webmakler.org/userfiles/file/difejejatadifajegugovi.pdfIn PDF document text
    • http://gimnazjum-krasiczyn.pl/img/userfiles/file/22795437749.pdfIn PDF document text
    • https://www.mediawerf.nl/bundles/store24backoffice/ckfinder/userfiles/files/pavuvofaginexefilefito.pdfIn PDF document text
    • http://sinostandards.net/upload/files/gofekamezel.pdfIn PDF document text
    • http://dailitara.lt/bites/uploads/file/dilusavegewotewujorixu.pdfIn PDF document text
    • http://www.liveartsaskatchewan.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614853f808a9a---tajokazafiwotevi.pdfIn PDF document text
    • https://kccegis.com/upfiles/content/file/20210913155820.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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f012.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF012 10764 bytes
SHA-256: a3d127ba712662db73183ce66f24ec6165f8237a4b1ba4f48f98861167727ed9
font_01_sfnt_off000108f9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x108F9 1948 bytes
SHA-256: b033f7fcbcd390b2cb396fbb5f03ef01f7ca9afc151f9d9df21604321f961cfa
font_02_sfnt_off000111f8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111F8 18652 bytes
SHA-256: 60905f4c9131c1f0d2ba1ee1eeca0b99fe01d951ef4084f018356266ab688ff0
font_03_sfnt_off00014323.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14323 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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