Malicious PDF — malware analysis report

Static analysis result for SHA-256 3519e32844db5ebb…

MALICIOUS

PDF

84.4 KB Created: 2021-04-05 03:57:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: d2e84a05318509690de10ab29722bd3d SHA-1: 728b8033555a534d8bae10b0b46dd111adcc5218 SHA-256: 3519e32844db5ebbe92724fd92e355147eddaad21af6d9026c4d2e1e67afd663
186 Risk Score

Malware Insights

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

This PDF was identified as malicious by multiple heuristics and an ML classifier, with ClamAV detecting it as a phishing trojan. It functions as a link farm, containing numerous external URLs pointing to other PDFs hosted on various domains, including suspicious ones like vilenefex.ru. The primary purpose appears to be directing users to potentially malicious content or phishing sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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.
  • 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 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://vilenefex.ru/123?utm_term=liabilities+and+assets+in+balance+sheet
    • https://cdn-cms.f-static.net/uploads/4459337/normal_605cf8ab707c9.pdf
    • http://fakosujonipej.iblogger.org/argumentative_essay_on_why_college_is_important.pdf
    • https://cdn.sqhk.co/wazewiput/glVjhDL/poe_essence_cheat_sheet.pdf
    • https://cdn.sqhk.co/bupewazadufa/iji1wTQ/world_swimming_championships_2019_medal_table.pdf
    • https://static.s123-cdn-static.com/uploads/4446914/normal_5fecc1c985575.pdf
    • https://cdn.sqhk.co/kekotenonaxu/gJshhzJ/1773983800.pdf
    • https://cdn-cms.f-static.net/uploads/4370737/normal_6011b1ede6d91.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.daltonmaag.com/
    • https://a765b249-d442-4b07-8ea9-8318d996b894.filesusr.com/ugd/902d29_fd80286538e44f0ebf731812e1ff7653.pdf?index=true
    • https://a2ae8793-a99f-480d-a3bc-849ef63d34f7.filesusr.com/ugd/cc207a_33446b04341e4757badca52e999112b7.pdf?index=true
    • https://c0e8410b-c394-4b36-8083-179878a46647.filesusr.com/ugd/d4b1dc_8ffaf582f13744758391566c32de80a8.pdf?index=true
    • https://37dcb74a-b492-4e6c-94d7-6984b04a3d7f.filesusr.com/ugd/01eaca_4066d65324ee431582bb1265590f6be4.pdf?index=true
    • http://lavodusepigixu.rf.gd/briggs_and_stratton_675_series_pressure_washer.pdf
    • https://9cc03a5b-da86-4a44-8f3d-15f7580f9586.filesusr.com/ugd/cac91c_8dbe5d37bb8144c4bae3deed26ff5218.pdf?index=true
    • https://c1cb471f-fc5c-4ef2-b3e1-4d0d0d09d135.filesusr.com/ugd/cc5b41_f9daa6b391974cbf86f1ef33830a516a.pdf?index=true
    • https://30c0d994-bee2-4d79-bc91-d4aaa7251653.filesusr.com/ugd/0962d9_89de8f15f56c4ff9a8304e17f5a0cb1f.pdf?index=true
    • https://uploads.strikinglycdn.com/files/1e666521-37a9-465c-a827-fd39744f7c79/foxelinajobogekuneb.pdf
    • http://jufakoxageponuz.rf.gd/34939913867.pdf
    • https://uploads.strikinglycdn.com/files/4d00c03f-2a92-4d5c-9627-7555fe289a56/elgato_hd60_pro_oder_hd60s.pdf
    • https://uploads.strikinglycdn.com/files/8c1f6000-5841-4e19-9c8f-d7c914d1b3ff/tuzosuwekuwulo.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000fe53.bin
befa306ef5dd50564cf9c3390a82f1bea64a485210832b9045ddf6422ce246b2
pdf-font-stream PDF embedded font (sfnt) at offset 0xFE53 4692 bytes
font_01_sfnt_off00010e2a.bin
5f295f865e8697fbde79aa44b062ab0ab5dfe34e1f374ee26db0323a9e3cd723
pdf-font-stream PDF embedded font (sfnt) at offset 0x10E2A 11628 bytes
font_02_sfnt_off000135c0.bin
cd94ef65598b1866d0653cdd88243d989fd81359c0e770c2d3a4858f1c2f6d34
pdf-font-stream PDF embedded font (sfnt) at offset 0x135C0 4324 bytes