Malicious PDF — malware analysis report

Static analysis result for SHA-256 b821529a64f9e3af…

MALICIOUS

PDF

76.3 KB Created: 2021-03-16 02:52:25 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-22
MD5: 18c1b8498fcb01a9439f5cd4b6acfa69 SHA-1: d3dfa80df6b9848803c09af3ead1e8d9f61bb1c3 SHA-256: b821529a64f9e3afbe1774b8ae3951e43d90f8ab75fea16cbb07fd7824eeee53
244 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a large number of embedded links, many of which point to known malicious redirectors or disposable hosting. This indicates an attempt to direct users to potentially harmful websites, likely for phishing or malware distribution. The ClamAV detection and ML classifier further support its malicious nature.

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
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://yafferge.ru/123?utm_term=i%2527+m+blue+piano+sheet+music In PDF document text
    • https://cdn-cms.f-static.net/uploads/4423137/normal_600af9a79e3a5.pdfIn PDF document text
    • https://cdn.sqhk.co/tinulafi/nP4hajJ/minecraft_herobrine_mod_1._14._30.pdfIn PDF document text
    • https://cdn.sqhk.co/xusikeko/iifPibl/75303140481.pdfIn PDF document text
    • https://cdn.sqhk.co/weralutofa/VcOI8Wz/collage_maker_app_download_for_mobile.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4374978/normal_5fe24e15bd971.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4450243/normal_5ff0da830840f.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4477630/normal_603cf861cf974.pdfIn PDF document text
    • https://cdn.sqhk.co/jimikafede/3mKjfha/tokaido_matsuri_expansion_review.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/5e5f7765-59df-49f8-913d-74e8dd940f40/jjrc_h20c_hexacopter.pdfIn PDF document text
    • https://471876dd-1950-42f1-a4b7-18bccbaeda70.filesusr.com/ugd/5d8976_f70acd2c226a418c9494a677559458aa.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/66c4a3f9-1ddc-4faf-b7e1-8311b33d14b5/how_to_explain_tone_in_an_essay.pdfIn PDF document text
    • https://b9b086bb-db5c-4c47-b99c-4ca3d8c772c1.filesusr.com/ugd/c090b7_32654c03c6ed4a97939cf3b20e4ebc08.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/f937e374-12c3-4685-a09c-2e429494f04a/29435271683.pdfIn PDF document text
    • https://451b78f8-089e-4d4d-bc4b-60abb621f7e6.filesusr.com/ugd/7ef0dc_8bdf39d0edaa4fa48599362e98e76df6.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/445d9a70-5789-4d13-80ca-e3a47def9613/bersa_thunder_380_concealed_carry_review.pdfIn PDF document text
    • https://6d4a8fb0-9a8a-4850-8aa1-2b5706121c9a.filesusr.com/ugd/ff2e72_7e6cf80e97c949249aeb83ef00bb650c.pdf?index=trueIn PDF document text
    • https://b5526579-b22d-45a0-8251-9885a72cf3eb.filesusr.com/ugd/0cd019_b90a575a1cee47f1a2671a6cda5ff249.pdf?index=trueIn PDF document text
    • https://2f8a6ab9-e864-4757-b083-6627a13f4c48.filesusr.com/ugd/405339_e822194399da488699ed70f7f7b6f38c.pdf?index=trueIn PDF document text
    • https://d5fd0048-bb8d-45a1-ba21-28d1cb0b7162.filesusr.com/ugd/5e8de6_915e310a422744c1abf350d19effe860.pdf?index=trueIn 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_off0000edf3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEDF3 5188 bytes
SHA-256: 0368ffcec7b91063acebac9ec1c4087ef9d907a72d9700b062d6a3dca2a624f6
font_01_sfnt_off0000ff6d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF6D 10748 bytes
SHA-256: 5c5d1905a742f7fb63fd251b7182a476a5a17f4de5e3a3c78ffcaf33982431fe