Malicious PDF — malware analysis report

Static analysis result for SHA-256 b55b51011cb5bee8…

MALICIOUS

PDF

99.5 KB Created: 2021-06-09 12:41:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: bee4379b7415f2a475939fac546d937c SHA-1: 66d721f5a700466921ef2ea86c2beec67083bc66 SHA-256: b55b51011cb5bee8e5e48151a18cd4901899e4505cf02c09e8e69e416989a0e2
186 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many pointing to disposable hosting, indicating a link farm or phishing attempt. The ClamAV detection and ML classifier strongly suggest malicious intent. While no scripts were explicitly extracted, the PDF structure and embedded URLs are indicative of a malicious document, likely delivered via spearphishing.

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://archism.ru/pbw?utm_term=queen+symphonic+concert PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4495849/normal_6025c452b63bb.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4475874/normal_603a42f19bdd0.pdfIn PDF document text
    • https://joxobupapi.weebly.com/uploads/1/3/1/4/131454586/be811944e75682a.pdfIn PDF document text
    • https://pexekakuxop.weebly.com/uploads/1/3/2/8/132814074/50f2ff73d777843.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4462046/normal_6068477bb60b7.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4485162/normal_601bcbcd06161.pdfIn PDF document text
    • https://noginoludaven.weebly.com/uploads/1/3/4/3/134374582/wugigokuti-putebu-nuguren-xenenimu.pdfIn PDF document text
    • https://kamefumude.weebly.com/uploads/1/3/4/0/134018396/nevokepegopetovisag.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4424026/normal_5fda3b81a826a.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://wuranosa.pbworks.com/w/file/fetch/144414786/cre_notes_form_4.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/d7f4a8b0-a158-46ab-8827-bd7469688404/how_to_be_a_team_leader_book.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/41262c82-824c-4994-9ce8-590eecf732e6/77616525994.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/d61e2e91-661b-49bf-847a-1ff30e8d9b82/how_to_automatically_download_songs_on_apple_music_iphone.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/93b65a59-cb72-4876-8078-061a8b11d1c9/built_in_water_dispenser.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/0c4f9ab4-9e64-42de-b801-90007726b37f/jopixu.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/a8366661-42ef-4f9a-8b0d-69f3eb56bb96/68258378743.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4605ac5d-eca4-4dfd-96c8-179711d9cd16/pidorose.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/e7a620dd-88cc-453e-a554-30d2d8cbd01f/microsoft_visual_studio_2010_premium_free_download_full_version.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/1933a7e3-9019-46c4-a350-5be7f575b0c5/apush_time_period_3_timeline.pdfIn PDF document text
    • http://vimadutukad.pbworks.com/f/the_land_of_stories_6_book_box_set_by_chris_colfer.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_off00014726.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14726 5092 bytes
SHA-256: 337ed1bce46b2d28921b107333e0085dd05b021eea77f69f2f4251d32a47e50b
font_01_sfnt_off0001585a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1585A 12712 bytes
SHA-256: a5ceb676465d813c8a48d36d23cf192dec664ceacf8fac295c11a80d284a76e0