Malicious PDF — malware analysis report

Static analysis result for SHA-256 537fa0bd43da3deb…

MALICIOUS

PDF

71.1 KB Created: 2021-04-21 23:07:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: 331d34e3da88c616b540977a1c6cb9fb SHA-1: 08ec12c90ae5cf90a3e69efc00339833c7a2fb54 SHA-256: 537fa0bd43da3deb98ac0d7ec537be1bd4d181e422499bbcb97c751b5411eda6
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

This PDF document was flagged by multiple heuristics, including a critical ClamAV detection and an ML classifier, indicating malicious intent. The presence of numerous embedded URLs, many pointing to potentially disposable domains, suggests a link farm designed to redirect users to malicious sites. While no scripts were explicitly extracted, the PDF structure and embedded links are consistent with phishing or malware distribution tactics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 5

  • 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.
  • 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://vectorcorp.net/sites/default/files/webform/resume/dufovomajaxavekasodulep.pdf In PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/mimixinaxeralowevowijut.pdfIn PDF document text
    • https://www.viachristi.org/sites/default/files/webform/89070061484.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/doxuwekuwazomiloxeri.pdfIn PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/72246142748.pdfIn PDF document text
    • https://www.jwico.com/sites/default/files/webform/66271497470.pdfIn PDF document text
    • https://www.woonsocketri.org/system/temporary/webform/kebadewanizokodijixupid.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/48232920683.pdfIn PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/61975266633.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/80098342864.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/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=what+is+a+claim+in+argument+writingPDF link annotation
    • https://lib.asu.edu/system/files/webform/midari.pdfIn PDF document text
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/ruwitik.pdfIn PDF document text
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/17420147243.pdfIn PDF document text
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/10713621665.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_off0000d77f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD77F 5316 bytes
SHA-256: f35a54eb3eae16a177b3e3fa981ee35780dcab08eb8bc0495d210d7f4a15a4a2
font_01_sfnt_off0000e97c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE97C 10768 bytes
SHA-256: 95e1d163af22666b936eadd55a27b5b9c5c82219c8cc9d3c4e158650eefb8a5b