Malicious PDF — malware analysis report

Static analysis result for SHA-256 ade4b525f74b7580…

MALICIOUS

PDF

81.6 KB Created: 2021-05-22 09:21:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 78079873f82699ea794f1830f4c7ab26 SHA-1: 7f9b80e7ac065c715c97477ba909d1c62cb4543f SHA-256: ade4b525f74b7580781933a3a8538b8a988dbc4a781541f5c44b159c351f20bf
164 Risk Score

Malware Insights

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

The PDF file contains a large number of external links, many of which are likely part of a link farm designed to improve search engine rankings. One of the primary links, 'https://vilenefex.ru/strik?utm_term=how+to+reply+for+probation+confirmation+letter', is flagged as unknown reputation and is likely the intended malicious destination. The presence of a 'download' button lure further supports a phishing or malware distribution attempt. ClamAV detection and ML classification confirm the malicious nature of the file.

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-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://vilenefex.ru/strik?utm_term=how+to+reply+for+probation+confirmation+letter
    • https://pevusipifo.weebly.com/uploads/1/3/4/8/134863194/zawul.pdf
    • https://cdn-cms.f-static.net/uploads/4493266/normal_603f372067cdb.pdf
    • https://vukosigubew.weebly.com/uploads/1/3/4/8/134860762/buvisakomot.pdf
    • https://zorusijumabek.weebly.com/uploads/1/3/4/8/134851431/boridajo-kagubaw-valefaripafim.pdf
    • https://jukirabupunux.weebly.com/uploads/1/3/0/8/130874410/4690003.pdf
    • https://cdn-cms.f-static.net/uploads/4370528/normal_6040e584e00c3.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.daltonmaag.com/
    • https://s3.amazonaws.com/sukobogixe/freestyle_wrestling_score_sheet.pdf
    • https://s3.amazonaws.com/nitidadufetenu/assistive_touch_pro_apk_2017.pdf
    • https://s3.amazonaws.com/moduxanakuri/yasin_suresi_hayrat.pdf
    • https://s3.amazonaws.com/loneminovu/38859401300.pdf
    • https://uploads.strikinglycdn.com/files/7da6a689-d761-46ca-b218-10f2ecb92159/night_circus_novel_synopsis.pdf
    • https://s3.amazonaws.com/nuxulikiwab/78504574796.pdf
    • https://uploads.strikinglycdn.com/files/dcfbfbd7-744b-42bb-9560-2a49ff68ff7c/dexuwepowedasu.pdf
    • https://uploads.strikinglycdn.com/files/d848e5e2-4fd0-4d94-9d0c-c52fff93ee1d/pudido.pdf
    • https://uploads.strikinglycdn.com/files/bd8d2e87-d351-4925-b31e-98b347d5d7d4/39180224281.pdf
    • https://uploads.strikinglycdn.com/files/de251e0a-29a0-402b-903c-1e1f97c3b44f/wujepa.pdf
    • https://s3.amazonaws.com/goneduzum/gcse_chemistry_the_periodic_table_answers.pdf
    • https://uploads.strikinglycdn.com/files/3527d68d-af0d-4847-8962-a5cde695ffc4/powerflex_755tm_user_manual.pdf
    • https://uploads.strikinglycdn.com/files/a13f66ad-4790-44ab-9572-afe335c41410/5_minute_bottle_crafts.pdf
    • https://s3.amazonaws.com/pavujiniz/80671269827.pdf
    • https://s3.amazonaws.com/pevarijidasalop/78401629846.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f3c1.bin
8a5739de43d80238e3722a2bbda8045ceef2fa91f54a0995c5ade2933df5057a
pdf-font-stream PDF embedded font (sfnt) at offset 0xF3C1 5068 bytes
font_01_sfnt_off000104eb.bin
b0b6c11a8a6b81482b631958c26feb5b057784325883de2966281f495ed2a757
pdf-font-stream PDF embedded font (sfnt) at offset 0x104EB 10456 bytes
font_02_sfnt_off000128b7.bin
cd94ef65598b1866d0653cdd88243d989fd81359c0e770c2d3a4858f1c2f6d34
pdf-font-stream PDF embedded font (sfnt) at offset 0x128B7 4324 bytes