Malicious PDF — malware analysis report

Static analysis result for SHA-256 9af23b19b651fad2…

MALICIOUS

PDF

81.6 KB Created: 2021-04-04 23:46:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-24
MD5: b8b6a660637857ae956932ce435818a3 SHA-1: 27e17cf64382103cffadeb2701ade88069851144 SHA-256: 9af23b19b651fad2331f53b20bd2584e8d8a5ca190ea8bca1f8fe46097f1198c
244 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 pointing to disposable hosting, a common tactic for SEO link farms. One of the embedded URLs, 'https://crophysi.ru/strik?utm_term=african+american+literature+phd+reading+list', is flagged as a known malicious redirector. The ClamAV detection and ML classifier further support the malicious nature of this document, likely intended to lure users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://crophysi.ru/strik?utm_term=african+american+literature+phd+reading+list In PDF document text
    • http://lbaranaydin.com/how_to_use_a_french_oveni35em.pdfIn PDF document text
    • http://gopikapi.22web.org/pepsi_cola_addict_book.pdfIn PDF document text
    • http://hookup153.site/the_song_of_scorpions_movie_trailer0vy6b.pdfIn PDF document text
    • http://xelipev.22web.org/notification_center_android_settings.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://5c3e38fa-bf2d-4cda-bfdc-19e9a39f2227.filesusr.com/ugd/b3ada4_f89da1a100264b02a364f5320133e496.pdf?index=trueIn PDF document text
    • https://95c758d6-fd33-43c6-b5d0-f1f55e07e946.filesusr.com/ugd/cb0188_e79afdeea8814df88552a53380999bd5.pdf?index=trueIn PDF document text
    • https://8bd0dbf5-62e0-4684-a95a-1d9666dfa34a.filesusr.com/ugd/e71694_5f224286053c4a459b43695eaf498ac9.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/sugowubuf/police_report_toronto_theft.pdfIn PDF document text
    • https://be1d055c-b83b-422e-9e68-1bf13cef350c.filesusr.com/ugd/5b1e3c_f76f3867070c42749bdb2909ffda1881.pdf?index=trueIn PDF document text
    • http://semeluja.epizy.com/sogerefufojivulexulud.pdfIn PDF document text
    • https://562c2315-396f-49d1-9e45-1236e049cb13.filesusr.com/ugd/ec0012_c47e2887c56f4c6ebd00ec9ef19653c5.pdf?index=trueIn PDF document text
    • https://09d56968-2ae9-412d-ad86-e67dc63a1c23.filesusr.com/ugd/e8b91f_623e748df26b45a5a35164936b07fd71.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/kukupunopedon/91521571189.pdfIn PDF document text
    • https://9eaa565e-fb97-40b4-b096-d6760803f699.filesusr.com/ugd/55e2c6_e05dcfb1a44748a585ae38f212ed7927.pdf?index=trueIn PDF document text
    • http://somuvezovo.rf.gd/puvijajenamavik.pdfIn PDF document text
    • http://babokad.epizy.com/kozoripitam.pdfIn PDF document text
    • https://s3.amazonaws.com/wazorixekunafob/save_game_minecraft_ps3.pdfIn PDF document text
    • http://zuwodiruvukima.epizy.com/writ_of_quo_warranto.pdfIn PDF document text
    • https://e4034479-4ead-418b-af8c-5be8dc72bdbe.filesusr.com/ugd/1e8759_8e99c484a4704ecd9155fb998d13d203.pdf?index=trueIn PDF document text
    • https://4bd9ed84-c80b-4837-bb2f-b1353ebfd8aa.filesusr.com/ugd/5a1791_f238bac88ce041848667a3b3f12bc4b0.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/seriposuj/adenocarcinoma_esofago.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_off0000fb7d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB7D 5556 bytes
SHA-256: 43fc9763abff0af72ac7ddcd1a6efc5c1f1323b5dda1ec71b04709c655c092e1
font_01_sfnt_off00010e3d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E3D 12144 bytes
SHA-256: d51a75c1c1301c1d89e07fe3cf2129b59fd8bd88507f33538499e4e0b6c6cdec