Malicious PDF — malware analysis report

Static analysis result for SHA-256 64bf3b6f98f619a5…

MALICIOUS

PDF

78.9 KB Created: 2021-04-26 00:12:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: 38efc42e7481ba40c80d4b21e30eae89 SHA-1: b5a2d2abea864c22277139238f2510ad93f63b96 SHA-256: 64bf3b6f98f619a5937b577da1148c50c0648ec15db596a353c962905466b6de
186 Risk Score

Malware Insights

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

This PDF file was identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The heuristics reveal it functions as a link farm, containing numerous external links to other PDFs hosted on disposable domains, suggesting a tactic for SEO manipulation or malware distribution. The presence of multiple external URIs and a link farm on disposable hosting strongly supports this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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 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://nipisod.ru/strik?utm_term=inkheart+book+4 PDF link annotation
    • https://cdn.sqhk.co/rotusorukazi/MkQhfaE/tower_defense_galaxy_legend_mod.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4369158/normal_5ffdefd3db1b3.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4486200/normal_5fdc7981d8a87.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4446162/normal_60047a29ed205.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4391326/normal_60052bdf18b47.pdfIn PDF document text
    • https://kelodopaseku.weebly.com/uploads/1/3/1/4/131406239/gavufubuvuwuj_rewemovekas.pdfIn PDF document text
    • https://kusejatakobex.weebly.com/uploads/1/3/1/4/131438299/bivem.pdfIn PDF document text
    • https://cdn.sqhk.co/govizanorev/TjhPgfx/pagevijedakiji.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4465259/normal_5ff7b313321f0.pdfIn PDF document text
    • https://cdn.sqhk.co/letarezetap/jjgcjiX/bluestacks_hd_app_player.pdfIn PDF document text
    • https://mitumeme.weebly.com/uploads/1/3/4/8/134879381/dusulosanide.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/68cd32cf-e129-4e77-abff-d706221314e4/libro_el_caballo_de_troya_en.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/f4255568-1dbc-40b5-a8e0-7f03fffd00cb/jexutasogufap.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/805bacc4-410d-48ce-b2bc-d8a2025e416b/vijuzenuvewijar.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/cbce81b4-cc3e-479a-9c51-e5b539da5822/ravakewolow.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/1eeb9c4c-2a2f-462f-9968-b57af01a3ef3/mind_over_markets_dalton.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/0cfac7e2-d4ff-4acb-8393-58c16ebc5ec1/gibimusuropevivazip.pdfIn PDF document text
    • https://s3.amazonaws.com/vukumesoj/integral_of_expxcos_x.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/fd3baec3-d0ea-480f-a79f-3b902adb0f39/445443729.pdfIn PDF document text
    • https://s3.amazonaws.com/lepefi/pedexapumibovu.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_off0000f85d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF85D 4792 bytes
SHA-256: a29fb9230b02f4a4a5da914af175e97c4dc6ff3cdf6ba23628c8f2598a760a70
font_01_sfnt_off000108aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x108AA 11308 bytes
SHA-256: 7d1803f81beef812573f41cdfd6c02c01c330eb7f7f036c54d2d1bf8d92a8e1b