Malicious PDF — malware analysis report

Static analysis result for SHA-256 668ec6155eaadbc4…

MALICIOUS

PDF

81.5 KB Created: 2021-06-02 05:10:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 00b838c70b6d066b53a3c964434944f4 SHA-1: e28ca0ad07ca3cb5bd25ddd6a67adeace8770421 SHA-256: 668ec6155eaadbc43f7525ce59644d0c1a44151ae79a4c6989064a0535f6cea0
156 Risk Score

Malware Insights

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

The file is identified as a malicious PDF by multiple heuristics and a machine learning classifier. It contains numerous external links, with one pointing to 'vilenefex.ru', suggesting a phishing or redirection attempt. The presence of PDF-specific heuristics like 'PDF_URI' and 'PDF_SEO_LINK_FARM' indicates the document's primary function is to host and link to external content, likely malicious.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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/123?utm_term=ocean+basket+cyprus+menu+pdf
    • https://kuwujevo.weebly.com/uploads/1/3/4/8/134864034/nifutu-kululaxi.pdf
    • https://kolivobaka.weebly.com/uploads/1/3/4/5/134500933/wonisijuditebej.pdf
    • https://cdn-cms.f-static.net/uploads/4447093/normal_60493d4730e84.pdf
    • https://raguloduw.weebly.com/uploads/1/3/4/0/134041620/8549703.pdf
    • https://cdn-cms.f-static.net/uploads/4421940/normal_606b107cbe79e.pdf
    • https://cdn-cms.f-static.net/uploads/4481280/normal_605f9fa343881.pdf
    • https://kivisibef.weebly.com/uploads/1/3/0/7/130775328/4586399.pdf
    • https://cdn-cms.f-static.net/uploads/4365627/normal_6037522c7c61c.pdf
    • https://cdn-cms.f-static.net/uploads/4476767/normal_60374c744a283.pdf
    • https://minavuxosedixif.weebly.com/uploads/1/3/4/5/134525921/weregipokena.pdf
    • https://cdn-cms.f-static.net/uploads/4381081/normal_604a61b6858c6.pdf
    • https://satalediveli.weebly.com/uploads/1/3/4/0/134018026/7440a9952340b8.pdf
    • https://cdn-cms.f-static.net/uploads/4375703/normal_600a07000083e.pdf
    • https://static.s123-cdn-static.com/uploads/4499300/normal_5fe1f2421a3d3.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.daltonmaag.com/
    • http://zabodovojif.pbworks.com/f/the_interview_1998_explained_reddit.pdf
    • https://uploads.strikinglycdn.com/files/52283e10-a1a3-4b6c-aae7-d978509ed860/the_negotiable_instruments_act_1881_multiple_choice_questions_and_answers.pdf
    • https://uploads.strikinglycdn.com/files/54e870c9-fcb1-4883-80bb-7b589db6d996/28950625946.pdf
    • http://zufogopojut.pbworks.com/f/best_2_player_board_games_reddit_2020.pdf
    • https://uploads.strikinglycdn.com/files/7a94b7d8-de76-4e48-8e09-5612c0130870/volume_formula_for_half_a_sphere.pdf
    • http://zajozote.pbworks.com/f/unseen_passage_for_class_4_with_questions_and_answers.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f3c0.bin
533c0c35cfa39b921046cf5320cdbafc580cd29084a224305536294c12c63e58
pdf-font-stream PDF embedded font (sfnt) at offset 0xF3C0 5328 bytes
font_01_sfnt_off000105c2.bin
a5bbeca8e852331c1869485fe88d7f2ed3cbfa4ea171a720b2d1990bac97101f
pdf-font-stream PDF embedded font (sfnt) at offset 0x105C2 10800 bytes
font_02_sfnt_off00012a88.bin
1062cd8ddf90f4344fa193b395386d5669df1a952e5759311ca261a71931f361
pdf-font-stream PDF embedded font (sfnt) at offset 0x12A88 4324 bytes