Malicious PDF — malware analysis report

Static analysis result for SHA-256 b21a5dd481c3ac9e…

MALICIOUS

PDF

89.1 KB Created: 2021-03-17 00:16:59 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-25
MD5: 9f39c20877e4fd2fbd3e07939bc450a1 SHA-1: b0df004603ec6ca465265a6bcb76b9b93e0df9c7 SHA-256: b21a5dd481c3ac9e25adef1583f1c6cef447fef9d42551eb546f3a85fe54249e
186 Risk Score

Malware Insights

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

This PDF document was flagged as malicious by ClamAV and an ML classifier. The file embeds a large number of external links characteristic of an SEO link farm. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://dafemum.ru/strik?utm_term=company+of+heroes+2+ardennes+assault+patch+download PDF link annotation
    • https://cdn.sqhk.co/bupewazadufa/jeih5le/getixoxixejozefanu.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4414176/normal_601bc4e9a5a9e.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4427287/normal_5fe4b9c6dcfe7.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4388279/normal_6002dbaa45cce.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4445115/normal_60221690524db.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4378406/normal_60361725c4aca.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4422638/normal_5fd68df54298c.pdfIn PDF document text
    • https://cdn.sqhk.co/vekuzajomugi/3QjikRe/17075005283.pdfIn PDF document text
    • https://cdn.sqhk.co/zozotetowa/gjVGhg3/smiling-_x_zero_classic_scary_horror_game.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4470040/normal_60512be894cb0.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4379045/normal_601aa8476951a.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4388046/normal_5fe5afe0935c2.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4403951/normal_604379fec2019.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4383913/normal_604f24ee18838.pdfIn PDF document text
    • https://cdn.sqhk.co/gasariba/r1jehau/3685097399.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4455902/normal_600fe9b71fb94.pdfIn PDF document text
    • https://cdn.sqhk.co/wadupaxi/m3hfIC0/18724304128.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://cfff6b0e-fc0f-4d9c-a983-c0e60c8b2bfd.filesusr.com/ugd/c637e3_25947ab84d2a4c10adec046e9a9c629a.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/299f26cb-78af-4ec4-a447-de43ad7f875a/zerabibina.pdfIn PDF document text
    • https://fbaba6ab-37cf-477f-82bd-e10a416eccda.filesusr.com/ugd/3c8574_c2d9e784d57d4b378f7be910f0551a88.pdf?index=trueIn PDF document text
    • https://ab60d57a-1f92-408f-9079-0b325776b613.filesusr.com/ugd/724fb5_dc88606852ef4fca8b8079e2863c8c4a.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/ae22ab1d-cb34-4ec7-8122-07205c1bb6fc/48317957531.pdfIn PDF document text
    • https://48e4e0df-78ce-4736-8797-27735e68dc67.filesusr.com/ugd/f3b179_8b6176ff8f404ee6bbf1ee454291a335.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/12196355-a4d5-452e-b0d8-11174c229fb0/massachusetts_drivers_permit_restrictions.pdfIn PDF document text
    • https://2c5a832e-93c4-4ab0-bef0-969ef348d747.filesusr.com/ugd/cc5daa_57aa70e1917d454ca78501b7ac12e3ac.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/47105854-fd1b-43e9-bb9b-21316f33ff3b/what_is_a_synonym_for_subjective_well_being.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4383bbb7-670a-46d4-a4ef-4c23ebe5bc79/fiwadosazudetapinezu.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
    • 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_off0000f9cc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9CC 5628 bytes
SHA-256: 3ef04b6e5a1b9063d19cec86ae36bafb759e34c9450b7606578b3b35965fde1a
font_01_sfnt_off00010cde.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10CDE 23304 bytes
SHA-256: f573af65774bc7bd5252c83584dc8d2f4b94eb7fcbfbd2566ee13e966b64ff9a
font_02_sfnt_off00014120.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14120 16068 bytes
SHA-256: 5d72d630640305d452d914085fd6c65e0d8125198bed8028c282d44fd0327be8