Malicious PDF — malware analysis report

Static analysis result for SHA-256 c91de78a1c18ec20…

MALICIOUS

PDF

77.9 KB Created: 2021-04-22 00:14:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-24
MD5: 6e97eec2a434316c9d0fc8aa8c08b06c SHA-1: 274499f1dc0225b6cb7b053467a520b92c5292e5 SHA-256: c91de78a1c18ec20f6b3119e63752bc26385c6287eb95ba2dca8d2d58450a9de
126 Risk Score

Malware Insights

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

The PDF document contains embedded URLs that redirect to external websites, with one notable URL being https://nipisod.ru/strik. Heuristic analysis indicates the PDF is a link farm on disposable hosting, and ClamAV detected it as Pdf.Phishing.Trojan. The ML classifier also flagged it as malicious. The document body, though partially obfuscated, suggests a lure related to differentiating between viral and bacterial colds to entice users to click the malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 5

  • 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://nipisod.ru/strik?utm_term=differentiate+between+viral+and+bacterial+cold PDF link annotation
    • http://leftoutclub.com/one_punch_man_blast_es_saitamahhgrj.pdfIn PDF document text
    • http://zunowugijose.22web.org/wto_agreement_on_subsidies_and_countervailing_measures.pdfIn PDF document text
    • http://nizixoj.iblogger.org/luziverakunurirasatopot.pdfIn PDF document text
    • http://vakekaninu.iblogger.org/google_sheets_ipad_freeze_row.pdfIn PDF document text
    • http://xiwezalibo.22web.org/zusopowumubaf.pdfIn PDF document text
    • http://vorgazme.com/lagimexajeseterumowopexa618xu.pdfIn PDF document text
    • http://baugroup.info/dsc_alarm_add_user_codewixyl.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://zuzenif.rf.gd/present_perfect_simple_exercises_intermediate.pdfIn PDF document text
    • https://e432c3f7-acc0-403b-bc7f-1b8c16782643.filesusr.com/ugd/6a4899_c1f465a292ea4faba07fe767d11bbcf0.pdf?index=trueIn PDF document text
    • https://92fa68c6-d088-48c5-94d9-776fe0504fc0.filesusr.com/ugd/5a053b_74ad515225bc4f989633a6cec9ad7721.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/feseni/brighthouse_financial_life_insurance_forms.pdfIn PDF document text
    • https://6b5d12f1-3bbc-48af-9ddb-5430d2fe15e7.filesusr.com/ugd/3bf302_5fbede81f0ea4a4e9a44e637499d6030.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/nademopor/audible_manager_needs_to_update_chrome.pdfIn PDF document text
    • http://xojukoliw.epizy.com/38431963127.pdfIn PDF document text
    • https://f72b89be-0fa6-41ee-8162-331329ef78ce.filesusr.com/ugd/95089d_0a9e0e4bb72940649c1fc54191b3d4d7.pdf?index=trueIn PDF document text
    • https://7c8f45b7-e058-4e27-bccd-8ee7dcb26900.filesusr.com/ugd/d5cf39_e3f8d5b15c6b4da7ad4b8f32d29f575b.pdf?index=trueIn PDF document text
    • https://cfecb619-c0f5-418d-ae9d-b1147643389f.filesusr.com/ugd/4cd51e_47cc9a0d83514cefa68475df4a4a1878.pdf?index=trueIn PDF document text
    • https://da9d63b4-fbfd-4f6f-88e7-06ac0d76355b.filesusr.com/ugd/ca300b_8b672c3c404a41bd9410ac1be03f9b0e.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/podawakumepewez/ford_digital_obd1_code_reader.pdfIn PDF document text
    • https://s3.amazonaws.com/woneketelak/sherlock_holmes_book_series.pdfIn PDF document text
    • http://rojumaninewevu.rf.gd/online_converter_to_to_ppt.pdfIn PDF document text
    • https://s3.amazonaws.com/vonusirukete/lafovu.pdfIn PDF document text
    • https://aefbb2f1-1cfc-4a48-aab2-d72547d84173.filesusr.com/ugd/2f3ac6_ea09328fb1bd4b379d0304c5e9c7586a.pdf?index=trueIn PDF document text
    • http://kojajopi.epizy.com/munufura.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_off0000f34f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF34F 5128 bytes
SHA-256: 3f8632bb632965ea8181da5c18aa437da723599810020259f42c3aeef199c318
font_01_sfnt_off000104ec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x104EC 10728 bytes
SHA-256: 6aca22b685d2e12cec0585decf6dfb070627a0deb6b915bedae3a70d4e3c3e49