Malicious PDF — malware analysis report

Static analysis result for SHA-256 91f3e3b6828d080c…

MALICIOUS

PDF

80.5 KB Created: 2021-09-23 16:02:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: a7911539af45edb9bee10f3064691970 SHA-1: 00523fcb46f04d9e22140e9c6f66d4a8db5423f3 SHA-256: 91f3e3b6828d080c7d3f2e2aa6b008808deac3f4b218b66ee7f84ba727148fd0
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The sample was detected as a malicious PDF by ClamAV and an ML classifier. It contains numerous external links, with one heuristic specifically identifying it as a link farm on disposable hosting. The presence of multiple unknown reputation URLs suggests an attempt to redirect the user to malicious content, likely for phishing or to download further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 http://print-resource.co.uk/ckfinder/userfiles/files/ziguwulilujinirifu.pdf In PDF document text
    • http://tubemakingmachine.com/uploadfile/files/12464102659.pdfIn PDF document text
    • http://asupuro.com/user_data/image/file/56139989923.pdfIn PDF document text
    • http://oshcongregation.com/userfiles/file/10560678656.pdfIn PDF document text
    • http://ebsenglish.net/_UploadFile/Images/file/59909577330.pdfIn PDF document text
    • http://miryangpension.com/FileData/ckfinder/files/20210922_C176249FAB1BDE50.pdfIn PDF document text
    • http://miroslaws.com/ckfinder/userfiles/files/safubidojixub.pdfIn PDF document text
    • http://steclotildehorton.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1613fbcfb0af11---nupumuruki.pdfIn PDF document text
    • http://vikohasanfiber.com/upload/files/32951540637.pdfIn PDF document text
    • http://aiaato.com/FileData/ckfinder/files/20210909_B3599C9A0B487AEA.pdfIn PDF document text
    • http://nfc.soo.jp/file/3325177579.pdfIn PDF document text
    • https://bizimpin.com/calisma2/files/uploads/88230842381.pdfIn PDF document text
    • https://advicezone.org.uk/wp-content/plugins/super-forms/uploads/php/files/3aaljvjrt6c7qcsvpd3ffjt4n9/6835581070.pdfIn PDF document text
    • http://nuk-amro.de/userfiles/file/47397152191.pdfIn PDF document text
    • https://ofcourselc.com/admin/uploadsfile/65876424346.pdfIn PDF document text
    • http://spadhotel.com/basefile/spadhotelcom/files/vopuvasipiwisinu.pdfIn PDF document text
    • https://techson-cctv.com/upload/file/4126446840.pdfIn PDF document text
    • http://poketomecam.com/uploads/files/bowagixajex.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BvfzZFkJO3s/uplcv?utm_term=animal+crossing+new+horizons+androidPDF 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_off0000d857.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD857 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f06e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF06E 10848 bytes
SHA-256: c06ea9509b581297de34b095024f05020a67fff864cdeb0d527d6856cd416efa
font_02_sfnt_off00010928.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10928 16936 bytes
SHA-256: 315c991ef9adcc6214e0a52c479ca16d8e651084ed4a51e84196577af77a209c

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