Malicious PDF — malware analysis report

Static analysis result for SHA-256 c5901921f8f6438e…

MALICIOUS

PDF

79.0 KB Created: 2021-09-17 16:48:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 43eb274a7146696f4b7fb741fe08855b SHA-1: 782b8a86798d59b98c3db3fc1533e2f934f604b4 SHA-256: c5901921f8f6438e1b347ca3005aed6b22b2bafc5d6b07ce3decce2757f1c747
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ML classifiers and ClamAV as malicious. A critical heuristic indicates it's a 'Clipboard command execution lure,' instructing the user to copy and paste content into a shell. This strongly suggests an attempt to facilitate the execution of a second-stage payload. While no scripts were extracted, the PDF contains numerous embedded URLs, with one pointing to a PDF file on a potentially disposable host, indicating a downloader or phishing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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
  • Clipboard command execution lure high SE_CLIPBOARD_COMMAND_LURE
    Document tells the user to copy or paste clipboard content into Run, PowerShell, cmd, or another shell-like execution context
  • 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://yellowstonewildlife.com/46221081562.pdf In PDF document text
    • https://cowichanmusicfestival.com/userfiles/file/63755177338.pdfIn PDF document text
    • https://boucherienabli.com/uploads/FCK_files/file/58003971786.pdfIn PDF document text
    • http://www.anapharmata.hu/ckfinder/core/connector/php/files/19130896245.pdfIn PDF document text
    • https://consultemergingmarkets.cubsindia.com/files/86809501687.pdfIn PDF document text
    • http://www.thunderesp.com/ckfinder/ckfinder.htmlfiles/wupukoxepawidupokefatunu.pdfIn PDF document text
    • http://www.sudaff.com/pics/file/jufepovenu.pdfIn PDF document text
    • https://regalcabs.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/161402eec477fb---semim.pdfIn PDF document text
    • https://prosaison.fr/userfiles/files/kujisawezixedevesejije.pdfIn PDF document text
    • https://mailing.crpm.ch/ck/ckfinder/userfiles/files/1672307451.pdfIn PDF document text
    • http://dongtienlamnghiep.com/upload/file/rupugi.pdfIn PDF document text
    • https://aannemingsbedrijfbarthulsbosch.nl/userfiles/file/41707038000.pdfIn PDF document text
    • https://www.chablis-gautherin.com/ckfinder/userfiles/files/61429410043.pdfIn PDF document text
    • http://www.trimbleexpress.sk/wp-content/plugins/formcraft/file-upload/server/content/files/161412a8d59db1---fidipinemuzisemarigema.pdfIn PDF document text
    • http://lineshare.net/upload/files/20210914192056.pdfIn PDF document text
    • http://warwick-ems.org/userfiles/file/27579499658.pdfIn PDF document text
    • https://kvizek.hu/ckfinder/userfiles/files/dubofu.pdfIn PDF document text
    • http://milwaukee.center/userfiles/file/9455066325.pdfIn PDF document text
    • http://wideanglepackaging.com/ckfinder/userfiles/files/42517533081.pdfIn PDF document text
    • http://whuntex.ru/userfiles/file/doxipesu.pdfIn PDF document text
    • http://bonfiremadigan.com/uploads/fckeditor/file/borejubefefuj.pdfIn PDF document text
    • https://faktxeber.ru/resimler/files/mikigedigugazegataxaro.pdfIn PDF document text
    • http://davidhammerstein.org/userfiles/file/50556782414.pdfIn PDF document text
    • https://npkfertilizerproduction.com/d/files/93229275005.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/FevRqgeaUVY/uplcv?utm_term=windows+run+apkPDF link annotation
    • 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_off0000cfda.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCFDA 10380 bytes
SHA-256: 44a48d24fec2a1b417fb24f101b0ddd936439084b2554205426f879399c94f0c
font_01_sfnt_off0000e77b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE77B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000ff8d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF8D 18208 bytes
SHA-256: 0c6bcf400d73f30dc4eff61083e75b09f7a24599173d3d7a6f3bb2d25322a414