Malicious PDF — malware analysis report

Static analysis result for SHA-256 6d797a72ca21a8c0…

MALICIOUS

PDF

78.6 KB Created: 2021-03-31 17:58:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 04ddf7861d802818f6173dd029e4e002 SHA-1: 5029c924faa94766f4d646bd415ce54b2c42a409 SHA-256: 6d797a72ca21a8c030f5c3239aabe7b36158aa9292157ff9bb378ab0cab2d394
156 Risk Score

Malware Insights

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

The PDF contains numerous external links, with a critical heuristic identifying a link farm designed to host multiple PDF files. One of the primary URLs, https://vilenefex.ru/award?keyword=brachioradialis+rehab+exercises+pdf, suggests a lure related to rehabilitation exercises, likely a pretext for a phishing or malware download attempt. The ML classifier and ClamAV detection strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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/award?keyword=brachioradialis+rehab+exercises+pdf
    • http://rutenowataba.iblogger.org/buzoxikosini.pdf
    • http://wobijovo.22web.org/tilogupomur.pdf
    • http://taygerr.com/osmosis_and_tonicity_worksheet3kfq0.pdf
    • http://lnstagram-help-businesss.com/72210395942dkxs8.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://tividisexagit.epizy.com/xevuneputisuvov.pdf
    • https://s3.amazonaws.com/fizup/2912330233.pdf
    • https://s3.amazonaws.com/bomupi/94410833700.pdf
    • http://nilezowavegat.rf.gd/oligopoly_market_structure.pdf
    • https://s3.amazonaws.com/sitok/amr_diab_albums.pdf
    • https://s3.amazonaws.com/zunaduxa/socratic_seminar_worksheet_4th_grade.pdf
    • https://37e0f79d-b0c1-4727-b76d-5b759c81288f.filesusr.com/ugd/9c66ff_bc5e18f14bb44d85b6be86a366c3327e.pdf?index=true
    • http://gidatefasu.rf.gd/understanding_body_language.pdf
    • https://s3.amazonaws.com/desenaz/avp_alien_vs_predator_mod_apk.pdf
    • https://s3.amazonaws.com/mukut/sutimibegilebizizuxabet.pdf
    • http://gozadowosib.rf.gd/celebrity_equinox_deck_plan.pdf
    • https://s3.amazonaws.com/tobaziw/hp_pavilion_dv6000_webcam_drivers_for_windows_7_32_bit.pdf
    • https://d872ce2a-2baf-4032-ab86-ab75b2f66d52.filesusr.com/ugd/338562_106d7bb86e094611a2d38ae1bf336a57.pdf?index=true
    • https://s3.amazonaws.com/lorifumofelu/54189418448.pdf
    • http://zekajawud.epizy.com/63950695057.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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f557.bin
1d80b1a5626beafa0365515b27092bc5122fce560fd0c42e7d8033ceed2a92fd
pdf-font-stream PDF embedded font (sfnt) at offset 0xF557 5500 bytes
font_01_sfnt_off00010802.bin
8b6de6eed11fd5f415a95c034109e8f4dbbe2948e4a760b82f19c56a08da0f5d
pdf-font-stream PDF embedded font (sfnt) at offset 0x10802 10816 bytes