Malicious PDF — malware analysis report

Static analysis result for SHA-256 e520e312210c3dd3…

MALICIOUS

PDF

80.6 KB Created: 2021-03-31 04:56:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: d299570201666e1ff7dadb5152440842 SHA-1: 9faebe7c8bf1aef519a3e453d6152e73ab0275ed SHA-256: e520e312210c3dd3c96de1b51451530eee720676a95945cf77e48173bf8fa689
164 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 it as a link farm. One of the primary links, 'https://zajinet.ru/award?keyword=biology+notes+pdf+for+competitive+exams', is presented as a lure for 'biology notes pdf for competitive exams'. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to download a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 6

  • 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
  • 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
  • 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://zajinet.ru/award?keyword=biology+notes+pdf+for+competitive+exams
    • https://cdn.sqhk.co/tixunadegu/gcoihL2/6461964614.pdf
    • https://cdn.sqhk.co/sexuzoropa/idjdcHd/prizefighters_2._7._6_mod.pdf
    • https://dimafivatoputir.weebly.com/uploads/1/3/4/4/134496040/c06be65cb8888.pdf
    • https://cdn.sqhk.co/tiviluluje/hPPifgg/boruwatazajuneguzizafoj.pdf
    • https://xumebarukez.weebly.com/uploads/1/3/4/6/134687090/kixutatatexisex-nexazinifuru.pdf
    • https://cdn.sqhk.co/zarifabidit/o9Ur7In/volume_of_prisms_and_cylinders_worksheet_tes.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/xixonu/gitav.pdf
    • https://uploads.strikinglycdn.com/files/625852ab-eb1c-4cb7-9f94-b4cdb9d1450a/fowiwinomidedakeborom.pdf
    • https://s3.amazonaws.com/jeduzizonox/12653096868.pdf
    • https://uploads.strikinglycdn.com/files/846e498b-e485-4bca-bb66-12f235fa9257/xbox_one_wireless_controller_custom_uk.pdf
    • https://uploads.strikinglycdn.com/files/ee94150b-6b3c-4dde-8835-acdd17176395/ti36x_pro_standard_deviation.pdf
    • https://uploads.strikinglycdn.com/files/787d510c-3061-45d5-8a80-e56aa91dd2a4/37306486214.pdf
    • https://uploads.strikinglycdn.com/files/dbc25974-1a7a-49d9-9910-8ffa9159b54f/rizofijifowevasumuxobexa.pdf
    • https://s3.amazonaws.com/wutogugej/encyclopedia_brown_sets_the_pace_summary.pdf
    • https://s3.amazonaws.com/dubiditiginowo/korean_drama_english_subtitles_free.pdf
    • https://s3.amazonaws.com/garorowa/how_heavy_is_a_55_inch_samsung_tv.pdf
    • https://s3.amazonaws.com/sutawowirosuvuv/ridobefilopepewafogepomor.pdf
    • https://s3.amazonaws.com/gateme/how_much_money_does_a_starbucks_barista_make_a_month.pdf
    • https://s3.amazonaws.com/vawoginele/professional_curriculum_vitae_samples.pdf
    • https://s3.amazonaws.com/magapeguwabe/gupodaga.pdf
    • https://s3.amazonaws.com/wupixufekijax/wudubajiv.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_off0000fcbc.bin
0eb52528cffb42a329e5c4391c070b00cbc21524eb943984b5018b2d8fb490d5
pdf-font-stream PDF embedded font (sfnt) at offset 0xFCBC 5752 bytes
font_01_sfnt_off0001105c.bin
0234468bd6092992c444d4a2c3ebd0b1dfed9ba7c3b770065ab6a579acf3d154
pdf-font-stream PDF embedded font (sfnt) at offset 0x1105C 10656 bytes