Malicious PDF — malware analysis report

Static analysis result for SHA-256 623555d12ed76dec…

MALICIOUS

PDF

77.8 KB Created: 2021-03-29 15:17:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 451fbfbb9d076f1483962a3a88484a0f SHA-1: 116c90f9e3189010f9bef031876fcb1276f028ed SHA-256: 623555d12ed76dec5b27c11dd5e663fe04a1a8dd3c44da898ec3a9326ef6e0fc
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file contains a large number of embedded external links, with one heuristic specifically identifying it as a link farm. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or SEO abuse. The document body is heavily obfuscated and unreadable, providing no direct clues to its purpose beyond the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://druttle.ru/strik?utm_term=canon+sx160+is+battery+problems
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/jifesu/75562915319.pdf
    • https://uploads.strikinglycdn.com/files/c9a20bfd-6440-467a-89b9-b613e392997d/12076599843.pdf
    • https://e114ad41-1367-46fe-a5fd-427bf640f69d.filesusr.com/ugd/a63c55_14ea6eef92364c1bb388e06b3e9c709e.pdf?index=true
    • https://502e425a-54a0-4661-a3e6-c6e116bdb13d.filesusr.com/ugd/10da26_5297ffbd9b734f05b4026404a7737c22.pdf?index=true
    • https://168d2a81-f750-40c6-a653-3787650f980d.filesusr.com/ugd/3bcfef_6572edf78b914bc6bcf935d271a0c4e6.pdf?index=true
    • https://170a7d3c-74f0-42f5-9ead-98ae292a4922.filesusr.com/ugd/a18aa6_1ee7387392ac48b3ac56aefa6a09f3d1.pdf?index=true
    • https://uploads.strikinglycdn.com/files/27a94e75-1a92-48e7-919c-97d75d1ad5b2/how_to_replace_toner_on_samsung_xpress_m2885fw.pdf
    • https://64f1e6a9-4530-4009-9f9b-67b91dd69f79.filesusr.com/ugd/76b6de_bcd93a356c20400985441c88163b9207.pdf?index=true
    • https://11627308-8c8f-4f08-99ed-0ad85160907d.filesusr.com/ugd/682d1c_a4983c53b2b6475fbca4763375c01b44.pdf?index=true
    • https://s3.amazonaws.com/fovezewi/android_9_update_for_galaxy_s8_plus.pdf
    • https://41be308f-8a64-4dec-8b30-4937605be974.filesusr.com/ugd/f042fe_3b6713c9d2564ee1b67faa91cf9df329.pdf?index=true
    • https://52b03d57-94e3-497b-b2ee-5a576b8f136c.filesusr.com/ugd/67ae49_b23597e45e274dcfb5015f0822e31bbc.pdf?index=true
    • https://uploads.strikinglycdn.com/files/e4f389c1-2a23-41ad-b0c1-54ec70c846fc/ergobaby_omni_360_newborn_head.pdf
    • https://8964868a-aef6-4da0-9a9b-29de7c28e0c5.filesusr.com/ugd/b910ae_6f292a4233af4ae5936533cace38e715.pdf?index=true
    • https://uploads.strikinglycdn.com/files/132c5f64-8fbf-4650-93ec-a481108da54f/does_tris_die_at_the_end_of_allegiant_book.pdf
    • https://c1f973cf-d719-4acb-8f9e-cd83ae4fb94d.filesusr.com/ugd/057766_3ab6b22b40a9472caf91b6747a09cfe6.pdf?index=true
    • https://661c91a2-68a2-4ae3-aaac-ef96b6cc7894.filesusr.com/ugd/b926a8_8c7168bb127b4baca67c1e4ce11c3a21.pdf?index=true
    • https://1df32be7-5e6a-491e-80e4-5c558052ef26.filesusr.com/ugd/e02e08_3806e05effef42939f56289ef89559da.pdf?index=true
    • https://0e733887-fd72-4d21-8b10-0a39cafbc931.filesusr.com/ugd/1e4d10_63076e17739e4fe282acc5a05e5c9169.pdf?index=true
    • https://141ebdc9-a3c9-4c6d-b8f9-366dbf139dec.filesusr.com/ugd/46bfb0_6661640ba59f4d829d5a2b5ecc7119b2.pdf?index=true
    • https://29aa9d28-cc9d-45fc-8d86-3718b5881c84.filesusr.com/ugd/74c34a_6063a6570bba426486763881acb207a4.pdf?index=true
    • https://5663e088-3595-439c-971a-5873693bee35.filesusr.com/ugd/e98895_99cb484500ed4497ab519e8b64007d44.pdf?index=true
    • https://c534e673-b245-4a6d-8787-855fe96db707.filesusr.com/ugd/e19215_7d9882b835ec47d4b2f41551c13d8602.pdf?index=true
    • 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_off0000f13c.bin
ca8f6dfc6906b3776a69eb58704001b266e9d306461035a99a192ef64a7f4b2e
pdf-font-stream PDF embedded font (sfnt) at offset 0xF13C 5528 bytes
font_01_sfnt_off000103f6.bin
f30df9adfbbeee71e2c296a7effdaa17c70f4fec8d6c7592edea6a1e54859d95
pdf-font-stream PDF embedded font (sfnt) at offset 0x103F6 11084 bytes