Malicious PDF — malware analysis report

Static analysis result for SHA-256 72bcede79b88a2b2…

MALICIOUS

PDF

72.5 KB Created: 2021-04-12 09:53:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: e3b5da22ac6b570708d31df023e514d9 SHA-1: fbdbf86d97ab637d23cc85e54cea23bd2effbb9d SHA-256: 72bcede79b88a2b2563a60f3e50b281765c7890d8bba96085eba201314c47b27
134 Risk Score

Malware Insights

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

The file is a PDF document that contains heuristics indicating it is malicious and potentially a phishing or trojan delivery mechanism. The presence of external URIs, particularly one associated with a download lure ('download dell supportassist offline'), suggests an attempt to trick the user into downloading a secondary payload. The ML classifier and ClamAV detection strongly support its malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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
  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://aboss.by/sites/default/files/webform/pibodanagulevegomenet.pdf In PDF document text
    • http://www.pacificsportfraservalley.com/sites/default/files/webform/90877516301.pdfIn PDF document text
    • http://portal-mysigma.com/system/files/student-proof/47432021317.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/julojulixizegusu.pdfIn PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/30199048500.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/19026354442.pdfIn PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/87400145234.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=download+dell+supportassist+offlinePDF link annotation
    • https://www.vub.be/sites/vub/files/webform/siwujomizawafoxewop.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/xadumiwedom.pdfIn PDF document text
    • https://www.healthdata.org/sites/default/files/resumes/muvebijamalixodimobowase.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/luzatebinibaxopititum.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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000db79.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB79 5128 bytes
SHA-256: 4883c30de70b3fff7a2ebc04feb74b479df511bb0da64ec3d41e3de730474a0c
font_01_sfnt_off0000ed12.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED12 11780 bytes
SHA-256: bb81528f0109140daff5c081164da09bf9d7efd4bb3df384be62eb0ed64c2d3a