Malicious PDF — malware analysis report

Static analysis result for SHA-256 531cb6bd3ef724b3…

MALICIOUS

PDF

73.5 KB Created: 2021-03-01 03:40:23 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-03
MD5: 84c8893f492042b70eb5932269a865b7 SHA-1: dbec785c4613e873b6773dcf878aa2fda67b212f SHA-256: 531cb6bd3ef724b367dce766965d4efcbbb23e7a494886d47ba3604816458f1b
192 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript T1203 Exploitation for Client Execution

The PDF contains multiple embedded URLs, with one identified as a known malicious redirector. The presence of a "download button" heuristic and the ML classifier's high confidence score further support a malicious intent. The document body, though heavily obfuscated, contains text related to a "Blues guitar chord scale generator", likely a lure to entice users to click the malicious link.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://yafferge.ru/strik?utm_term=blues+guitar+chord+scale+generator In PDF document text
    • https://cdn.sqhk.co/sezelijimofi/jiihgeg/death_road_2_canada_apk.pdfIn PDF document text
    • http://xudisoda.66ghz.com/casio_fx_991_es_plus_c_manual.pdfIn PDF document text
    • https://cdn.sqhk.co/mitejapeki/jhjejjb/message_ringtone_apple_download.pdfIn PDF document text
    • https://cdn.sqhk.co/kifukuvitog/d4Kjf1V/lolutirulewuderas.pdfIn PDF document text
    • https://cdn.sqhk.co/vavusiwi/phciegd/stickman_fighter_dragon_ball.pdfIn PDF document text
    • https://cdn.sqhk.co/pijujuweg/hjCjc9n/cartoon_tv_series_free_download_for_mobile.pdfIn PDF document text
    • https://cdn.sqhk.co/tomakaxizo/Ulkx6rk/neighbors_federal_credit_union_goodwood.pdfIn PDF document text
    • https://cdn.sqhk.co/zisenusaf/Sqrhhhg/programmable_character_generator.pdfIn PDF document text
    • http://gulidomirebo.22web.org/how_to_say_the_catholic_rosary_beads.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • http://bufalirafuma.epizy.com/58447865725.pdfIn PDF document text
    • http://motinekan.epizy.com/letter_format_for_payment_acknowledgement.pdfIn PDF document text
    • http://bopudax.epizy.com/45129203727.pdfIn PDF document text
    • https://s3.amazonaws.com/wipotegadodorek/zokurowir.pdfIn PDF document text
    • http://tiwatimab.atwebpages.com/37400298825.pdfIn PDF document text
    • http://bejiteviv.epizy.com/dalex_finance_annual_report.pdfIn PDF document text
    • https://s3.amazonaws.com/sazixipame/mabufew.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_off0000d388.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD388 5132 bytes
SHA-256: 5f7910762ac0b9bd34c6ebc953b2a8a8437fbeffd165e9dd70823963dfc2c1f4
font_01_sfnt_off0000e4eb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4EB 11024 bytes
SHA-256: 6f6027c07c1e4f5cf9f070145a7f6428ac101ee51b6a63fd0f99effcd8172204
font_02_sfnt_off00010ac9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10AC9 4324 bytes
SHA-256: 0d0f64e27578eb124b8bc81c7eceacdd166e22eddd95c81328e9fbd7de2a6333

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