Malicious PDF — malware analysis report

Static analysis result for SHA-256 bcb1f3e363b4668f…

MALICIOUS

PDF

74.4 KB Created: 2021-05-30 03:46:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-25
MD5: f6f91889886be0842d4125cb9b4ead10 SHA-1: caf3ad17710f6f99454d703076a08d367675305d SHA-256: bcb1f3e363b4668f5723d31637e3bdc96e64fc4ba19cf7ec5721122d48242dd7
186 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many hosted on disposable domains, indicating a link farm designed to distribute traffic to potentially malicious sites. The ClamAV detection and ML classifier strongly suggest malicious intent, likely for phishing or malware delivery. The presence of external URIs and a link farm points towards initial access via spearphishing, with the links serving as a mechanism for further exploitation.

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 contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://vilenefex.ru/strik?utm_term=how+to+set+temperature+on+heat+pump PDF link annotation
    • https://static.s123-cdn-static-d.com/uploads/4502336/normal_60b18e4d552ba.pdfIn PDF document text
    • https://rigavimiba.weebly.com/uploads/1/3/0/8/130814992/bagabowudobovelaj.pdfIn PDF document text
    • https://static.s123-cdn-static-d.com/uploads/4383165/normal_60afe3313108c.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4453117/normal_606b7f8f34fbc.pdfIn PDF document text
    • https://danuxuzajuzawo.weebly.com/uploads/1/3/4/7/134768569/kepununemagopoja.pdfIn PDF document text
    • https://jaxuvoxet.weebly.com/uploads/1/3/5/9/135979876/90af12b.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4401714/normal_5ff28a0777e11.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4414869/normal_60688ef2639b6.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4449184/normal_6045f77cbf0c4.pdfIn PDF document text
    • https://geselumagema.weebly.com/uploads/1/3/4/6/134695037/xulasanesifuvok.pdfIn PDF document text
    • https://sejumajofejopib.weebly.com/uploads/1/3/2/7/132740214/texuligagex-fatijoxaf.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4414487/normal_604145bb795b0.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4465249/normal_60395da15f19e.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4372983/normal_600ead0c89072.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4366965/normal_600346654a31f.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4465403/normal_6060e8ca78005.pdfIn PDF document text
    • https://motonikepo.weebly.com/uploads/1/3/0/7/130739202/cd88ad539a0b3.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4373261/normal_600d7c4b69af8.pdfIn PDF document text
    • https://jojimixumomural.weebly.com/uploads/1/3/4/4/134438106/b8043d7dd52.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/61fdbbed-ccb0-4738-83ad-05de6a347ff8/what_is_offsite_storage.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/6e88e7db-a36f-4557-9608-c56bdf6545ab/jojim.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_off0000e64d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE64D 5080 bytes
SHA-256: 44aeb2c36fb0a08fa77fd0dcfd586c42ffb2ea75f53195e3a32ab76a0d679d70
font_01_sfnt_off0000f772.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF772 10908 bytes
SHA-256: 8b8c6c2f71815d9c4c31ca5064a62463db0433dfead21b5e92d61aa446ea2654