Malicious PDF — malware analysis report

Static analysis result for SHA-256 d4b5948b5cca8c86…

MALICIOUS

PDF

77.2 KB Created: 2021-05-30 16:11:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: c249de450c07211d8ebdd3d808d8a9b9 SHA-1: a903a83d0ab1d6f4accfbc9858af0abd9f4ec28c SHA-256: d4b5948b5cca8c861ad41ba5cb764a004730175c923c368299419158517dd4cf
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, with one heuristic specifically identifying it as a 'PDF_SEO_LINK_FARM'. The primary malicious URL, 'https://xajibur.ru/123?utm_term=a+certification+exam+guide+pdf', is likely used for phishing or to redirect to malicious content. ClamAV and an ML classifier also flagged this PDF as malicious, indicating a high likelihood of malicious intent.

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-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://xajibur.ru/123?utm_term=a+certification+exam+guide+pdf
    • https://cdn-cms.f-static.net/uploads/4475565/normal_602a14e3f32b0.pdf
    • https://cdn-cms.f-static.net/uploads/4409814/normal_603f0070b036b.pdf
    • https://cdn-cms.f-static.net/uploads/4450426/normal_603882fc8f5dd.pdf
    • https://cdn-cms.f-static.net/uploads/4444884/normal_606cb974530e4.pdf
    • https://mubelumovetofap.weebly.com/uploads/1/3/1/8/131856402/voxuremugebobedi.pdf
    • https://cdn-cms.f-static.net/uploads/4379220/normal_6053f03ba852e.pdf
    • https://cdn-cms.f-static.net/uploads/4451208/normal_602bb5d4b8c69.pdf
    • https://static.s123-cdn-static.com/uploads/4479435/normal_5ffc4f9653713.pdf
    • https://static.s123-cdn-static.com/uploads/4409606/normal_5ffe2057d1ec2.pdf
    • https://mutodebubopuvom.weebly.com/uploads/1/3/4/3/134373551/17f96.pdf
    • https://cdn-cms.f-static.net/uploads/4459324/normal_605f2e781f37d.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/61c62c46-e1c9-4401-86e0-6ca3dd510e9e/kufalagujijusi.pdf
    • https://uploads.strikinglycdn.com/files/3f6dc094-192a-42a6-9107-4fafbe4bbf6f/yksek_lisans_tez_savunma_sunumu_rnekleri_powerpoint.pdf
    • https://uploads.strikinglycdn.com/files/6523252c-b782-49e2-a10c-90a07ffc9624/bivaporima.pdf
    • https://uploads.strikinglycdn.com/files/f4d21d8b-6ad5-468b-87e0-52f0f3c8b437/popcaan_friends_like_these_lyrics_download.pdf
    • https://uploads.strikinglycdn.com/files/9ed78bd7-85b2-46a7-bc2e-43db87fe4791/baby_goats_for_sale_colorado.pdf
    • https://uploads.strikinglycdn.com/files/35f4e062-79ce-4bd5-97b7-f18e557a3056/msi_gtx_970_gaming_4g_weight.pdf
    • https://uploads.strikinglycdn.com/files/10cdf241-7e44-4892-86b6-99aa181bc3c6/how_to_use_kindle_lending_library.pdf
    • https://uploads.strikinglycdn.com/files/cb73fdfa-8b08-40a8-a9e1-8fe3c6fe716d/wwe_2k17_caw_formulas.pdf
    • https://uploads.strikinglycdn.com/files/6beba235-d26a-4bb6-b0dc-e20444b4aee7/associated_press_ap_style_guide.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_off0000f11c.bin
d14e7bcd2d0b0f89263a741d980423439bfaaf69b9f36b20198628b1b5d807e6
pdf-font-stream PDF embedded font (sfnt) at offset 0xF11C 5320 bytes
font_01_sfnt_off0001032b.bin
c00e990b6082642558df8edc1bd18f60b6cca83eaeef0918e2fc8cf65ee5817f
pdf-font-stream PDF embedded font (sfnt) at offset 0x1032B 10916 bytes