Malicious PDF — malware analysis report

Static analysis result for SHA-256 1caeda2cfe51c086…

MALICIOUS

PDF

78.5 KB Created: 2021-04-09 04:17:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 994c996e37ba62f220d91fcf6e4ec399 SHA-1: e9103fa380329b272f2617cbe553d214aca9ce11 SHA-256: 1caeda2cfe51c086de6d9bc59d34240a3282e072fd94d4ca7cf3e0e90d615721
186 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains a large number of external links, many pointing to disposable domains, suggesting a link farm used for SEO poisoning or phishing. The primary URL, https://seumenha.ru/strik?utm_term=calculo+integral+unidad+4+definicion+de+sucesion, is likely part of this malicious infrastructure. Although no scripts were explicitly extracted, the PDF structure and heuristic firings strongly suggest it's designed to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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://seumenha.ru/strik?utm_term=calculo+integral+unidad+4+definicion+de+sucesion
    • https://cdn-cms.f-static.net/uploads/4394077/normal_601a57fb90442.pdf
    • https://static.s123-cdn-static.com/uploads/4451039/normal_5fdecc05049bc.pdf
    • https://waferipesor.weebly.com/uploads/1/3/5/3/135307907/xasivelop-pizadugifo-xuganokojok-pepide.pdf
    • https://cdn-cms.f-static.net/uploads/4459776/normal_601e16f533d1d.pdf
    • https://static.s123-cdn-static.com/uploads/4486037/normal_5fcb934057bd7.pdf
    • https://sibitolifi.weebly.com/uploads/1/3/4/7/134732274/2706748.pdf
    • https://static.s123-cdn-static.com/uploads/4486200/normal_5fef670f44d7c.pdf
    • https://zovakilezogavi.weebly.com/uploads/1/3/1/1/131163957/3289167.pdf
    • https://nitavadokeja.weebly.com/uploads/1/3/1/1/131163909/fowasojufudozilamup.pdf
    • https://banafazag.weebly.com/uploads/1/3/4/3/134325205/wubet_xuvevonetivat.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://30b7a97f-6117-4fff-8876-4b3c2220b6c6.filesusr.com/ugd/15cd4d_558c89bf7187431788e7c2eed32ab2df.pdf?index=true
    • https://s3.amazonaws.com/fowonaxul/davupejilevuvotaligeradu.pdf
    • http://jovuxajir.rf.gd/2018_mathematics_grade_12.pdf
    • http://xajovezosesazu.epizy.com/18th_amendment_to_the_constitution_of_pakistan.pdf
    • https://76a725e8-946c-4ae9-9249-cda469d35108.filesusr.com/ugd/83c8cc_c84e41afeb5b4e24b2b432ceaedbae09.pdf?index=true
    • https://s3.amazonaws.com/kovibu/westworld_season_1_episode_5_script.pdf
    • https://s3.amazonaws.com/nosepevozux/gmat_official_guide_2019_gmatclub.pdf
    • https://35b1a599-9f45-4897-82ce-59a931fc5495.filesusr.com/ugd/daca0d_8e04a77ba9ca41dba79fcf132bf47308.pdf?index=true
    • https://23751d96-d7b3-42ca-b8ca-e459b671ea95.filesusr.com/ugd/7de994_99ae90badad64b99a97ed21742b2dc02.pdf?index=true
    • https://246406bc-bb0d-4f29-baed-d8a6153a9543.filesusr.com/ugd/3ddeef_f311b7bab5a6447b9a4e3239cc84ad27.pdf?index=true
    • https://9c8f49e5-5895-4656-bc53-c560b1a0ede3.filesusr.com/ugd/0f7a6f_3d8b812854d94bde8e7c656df4064431.pdf?index=true
    • https://1094d5c0-a920-47c7-a1de-7e2d56a92d84.filesusr.com/ugd/47b1e8_f3eaa37e9c824bdb8cae9796d65e9ecb.pdf?index=true
    • https://e50eee24-2d95-422d-8083-6f618d95927b.filesusr.com/ugd/594ae5_b491398492f8467e953c13c397e7551c.pdf?index=true
    • https://ebd157e6-94c3-4ff5-b3ab-516f87acbde6.filesusr.com/ugd/e87473_3ce32104593d402b8d70f14f03e04b0e.pdf?index=true
    • https://1cbf0fd9-62af-4102-a3dc-982f361539e7.filesusr.com/ugd/bfbc46_663e0eb5c2ac4a6daece631fb17549b8.pdf?index=true
    • 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000efde.bin
90831d566b9bcd365c4ac484cad78e3e9481202fe4bda0e0f78ac63f402bbe76
pdf-font-stream PDF embedded font (sfnt) at offset 0xEFDE 5184 bytes
font_01_sfnt_off00010192.bin
a72de3aaa3107f8759e639c811b55ce85805cad8ad26d1796236039f086b2c80
pdf-font-stream PDF embedded font (sfnt) at offset 0x10192 12640 bytes