Malicious PDF — malware analysis report

Static analysis result for SHA-256 b0b8bef0ac7c1912…

MALICIOUS

PDF

78.1 KB Created: 2021-03-20 06:44:59 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 731a8958f2d762170212461ed63ed5df SHA-1: 5b357133c199f8d2b511136b1e1e0d355b1b7d3b SHA-256: b0b8bef0ac7c1912fdaa2df88809785aa9ac630b6eebe65ae072360b90b92e8d
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, flagged as a link farm, with one prominent URL suggesting a lure related to grammar books. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware distribution. No scripts were extracted, but the PDF structure itself facilitates the attack.

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-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://xezojetit.ru/award?keyword=best+british+english+grammar+book+pdf
    • http://mitatizizuje.mypressonline.com/wassce_biology_syllabus.pdf
    • https://cdn-cms.f-static.net/uploads/4374953/normal_603016525522c.pdf
    • https://static.s123-cdn-static.com/uploads/4494166/normal_5fc7699b5b0f3.pdf
    • https://cdn-cms.f-static.net/uploads/4407066/normal_6024a6d9ac63a.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/80e6a7a4-b3a5-4ff2-b410-530051f8a32b/kepavegitotopiresazomij.pdf
    • https://uploads.strikinglycdn.com/files/0be21825-7491-4bc0-8525-d5d48c440fa0/72623477238.pdf
    • https://uploads.strikinglycdn.com/files/59afdedf-b466-42b8-9085-1904b162fd44/how_to_reset_hp_printer_2545.pdf
    • http://viwuwijagabote.myartsonline.com/bixegolasexejijer.pdf
    • https://17673d3b-e5d0-4e0e-8211-f079fadf35f5.filesusr.com/ugd/13ae68_3d2640b1cd9948e091d9830dc42bd40d.pdf?index=true
    • https://9cf93ecd-64ee-4ad6-afcc-f350577a7522.filesusr.com/ugd/c4dbd3_de5701f6b6c1455d9bd67e06acc29c7f.pdf?index=true
    • https://uploads.strikinglycdn.com/files/3ec31b0d-8e53-46df-9c31-4ab14da111ba/is_the_kings_speech_based_on_a_true_story.pdf
    • https://s3.amazonaws.com/megodipewukitoj/easy_christmas_piano_sheet_music_free.pdf
    • https://uploads.strikinglycdn.com/files/e03b1a9e-1ce1-4f0f-a4c8-ac8cb6961c5e/which_of_the_following_is_an_example_of_thermal_radiation.pdf
    • https://s3.amazonaws.com/sugosubexez/how_to_setup_appium_using_android_studio.pdf
    • https://uploads.strikinglycdn.com/files/2f7e2f8c-4f71-4da4-8233-d5e68438e59d/puerto_rican_recipes_rice_and_beans.pdf
    • https://s3.amazonaws.com/wekibik/shinee_romeo_album.pdf
    • https://f6ea5e03-7e7c-4dce-82ee-fd5d223759ef.filesusr.com/ugd/d203ad_f3a3c2855f7b46d597d87f8d94224b00.pdf?index=true
    • https://uploads.strikinglycdn.com/files/a5887ef3-3b99-42d9-bcd5-959fe942939a/fipusuwifowugu.pdf
    • https://uploads.strikinglycdn.com/files/93ab67d6-99c8-4a3b-aba2-1577747f590c/wuxesupoze.pdf
    • https://uploads.strikinglycdn.com/files/587b6c48-9be0-4afd-b1ea-69252070cf4f/libeduwanonagurelejono.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_off0000f1a1.bin
50b371d64dcf453c7ed6dc3d6cfa4b800eeada7c061f1dd5ca7a770e5f7b3061		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF1A1 5708 bytes
font_01_sfnt_off000104de.bin
0648197f2900bba08d4514da0e8336de347d9d3d483ae14ecfc96a866af44731		 pdf-font-stream PDF embedded font (sfnt) at offset 0x104DE 11204 bytes

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