Malicious PDF — malware analysis report

Static analysis result for SHA-256 f8d36ac81c19751f…

MALICIOUS

PDF

100.5 KB Created: 2021-04-06 16:27:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: b00f1f4568226b3ab761b93f73db05e1 SHA-1: 209b996a8c631bf335d276a943d3c2a1548c22fb SHA-256: f8d36ac81c19751f9a27e541d121975366be5d0ab92224a1c238dbc2a7e6e038
186 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, with ClamAV identifying it as a phishing trojan. It contains a significant number of external links, many pointing to disposable hosting, suggesting a link farm designed to redirect users to malicious sites. The document body is heavily obfuscated and unreadable, providing no direct clues about its specific purpose beyond the presence of URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • 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/award?keyword=agriculture+nic+writereaddata+pdf+file+2020 PDF link annotation
    • https://cdn.sqhk.co/poronujefino/djfieZW/how_do_granny_smith_apples_taste.pdfIn PDF document text
    • https://cdn.sqhk.co/tiluzegata/hgiiUgg/zediroloki.pdfIn PDF document text
    • http://raicen.com/fire_sniper_combat_apk_modpi7s2.pdfIn PDF document text
    • http://stavki-na-sport.site/146306171101jvgy.pdfIn PDF document text
    • https://cdn.sqhk.co/keridola/zow3gcA/34810863275.pdfIn PDF document text
    • https://cdn.sqhk.co/bitizulokiva/bgdjjFU/96865639470.pdfIn PDF document text
    • http://superheatbelt.xyz/space_maintainer_lepasanxelts.pdfIn PDF document text
    • http://about-central.com/75313527200lulb7.pdfIn PDF document text
    • https://lupipoga.weebly.com/uploads/1/3/4/4/134402738/valolab_tudagavarete.pdfIn PDF document text
    • https://fomunova.weebly.com/uploads/1/3/4/6/134684458/zapolof.pdfIn PDF document text
    • https://wagidojinubem.weebly.com/uploads/1/3/1/4/131438567/migemerosasok_vugozo.pdfIn PDF document text
    • http://jawunefuda.mygamesonline.org/shl_logical_reasoning_test_with_answers.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://df9240ce-57b4-430e-a582-521170ca5232.filesusr.com/ugd/10b03a_a5f25a1e27494062ab5d77392bd17f63.pdf?index=trueIn PDF document text
    • https://013c3ecd-17dd-4738-ad87-554153c764a5.filesusr.com/ugd/36f25b_acf21f88965f4028b3e99be3a024f7d9.pdf?index=trueIn PDF document text
    • https://8c330184-3457-40de-b162-e34763a77ed1.filesusr.com/ugd/0aae61_c40dfa463cff4e84945db17c795d06ac.pdf?index=trueIn PDF document text
    • https://e4034479-4ead-418b-af8c-5be8dc72bdbe.filesusr.com/ugd/1e8759_39d2352854604af28754d47061f5390f.pdf?index=trueIn PDF document text
    • http://rabatelekovufar.myartsonline.com/cv_format_for_civil_engineers_freshers.pdfIn PDF document text
    • https://42190e62-4dca-482d-a077-ae7b222d7779.filesusr.com/ugd/b91392_05c6c0a88fd54ed4803737c583ac3910.pdf?index=trueIn PDF document text
    • http://ziwivazud.onlinewebshop.net/subtraction_with_regrouping_word_problems_worksheets.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00014a9a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14A9A 5500 bytes
SHA-256: 10d3796f7e5ee69bf06edd5b7d54b2af5cad9ff25bd68d92e8774cc647c72496
font_01_sfnt_off00015d7a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15D7A 11128 bytes
SHA-256: 61d29857cdc638d439ff8e56b4cbe482d3cd955359d0b94bf9f65909554c5105