Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b9d16e1a66da8d0…

MALICIOUS

PDF

77.6 KB Created: 2021-03-20 10:50:52 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-07
MD5: e7406b98f48c99c44fb4e25a3d1d7efd SHA-1: efcf1cab013fbbce8f1d90e89e7446d40d4f92d1 SHA-256: 4b9d16e1a66da8d019f14890e702d7b01464863796f7d5a6e21c8c18d12168b1
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, indicative of a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or SEO manipulation. The primary attack pattern involves directing users to potentially malicious external content via embedded URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9988

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://resalured.ru/award?keyword=handbook+of+biochemistry+and+molecular+biology+pdf PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4367633/normal_5fea3036303c1.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4448976/normal_6037d89870f43.pdfIn PDF document text
    • https://cdn.sqhk.co/tibakekavero/Igj3hen/best_call_blocking_for_iphone.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4393759/normal_60375cf0f07a6.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4385612/normal_5fedd49363040.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4383917/normal_6041c7eabdd60.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4454684/normal_5ffa44b0420de.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4496585/normal_6046f0a2a253b.pdfIn PDF document text
    • https://cdn.sqhk.co/zururodi/ghqRjgq/66607310579.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4474720/normal_60556aadb7ca2.pdfIn PDF document text
    • http://mukerixiwe.22web.org/lupome.pdfIn PDF document text
    • https://sevafigetof.weebly.com/uploads/1/3/4/9/134902911/c0295968f18.pdfIn PDF document text
    • https://rijagadufe.weebly.com/uploads/1/3/1/6/131606992/5bf8af.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4378605/normal_604cd1a751195.pdfIn PDF document text
    • https://cdn.sqhk.co/kanemili/etggZCN/sunday_school_lesson_plans_for_youth.pdfIn PDF document text
    • https://cdn.sqhk.co/rinugezig/ATZiejd/gunship_battle2_vr.pdfIn PDF document text
    • https://pefolasonej.weebly.com/uploads/1/3/4/9/134901659/2161799.pdfIn PDF document text
    • https://cdn.sqhk.co/simikitivo/ijYKham/35102332917.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4475987/normal_5fcbccf354b8c.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/83a5c135-79ed-4282-8b12-358aaa5893b0/zanafevaduzukegak.pdfIn PDF document text
    • http://toxebejoni.rf.gd/made_to_stick_book_club_questions.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4de9ebec-08d9-4d12-92f8-bdf5e3d5c512/bezigif.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/a7bd3de9-6a09-4ccf-a93c-8f53e670d88a/how_to_set_odometer_on_cateye_velo_wireless.pdfIn PDF document text
    • http://besowotu.epizy.com/59008625741.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e637.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE637 2828 bytes
SHA-256: 2f32373152b86590eb5c993bf8dbb57d20fc33770b92bc1ec6b5fd985d660553
font_01_sfnt_off0000f040.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF040 5836 bytes
SHA-256: 5b897ab10f194b96fa98db293d2dc201350db8d5a2046698376c051d19f71c8e
font_02_sfnt_off000103f8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103F8 10508 bytes
SHA-256: eae5b42d3fc6b10a18f1abb55a6816680070a7d8bbad06b7632f91e3fb6d4306