Malicious PDF — malware analysis report

Static analysis result for SHA-256 36cd82a055e3a94c…

MALICIOUS

PDF

74.7 KB Created: 2021-04-02 02:42:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-07
MD5: c75f2d6c2434a6295db6150e0a36bf04 SHA-1: 4d1eaa104fe13649ed5f53de4cd3061ad4f3d054 SHA-256: 36cd82a055e3a94cdf951b6586e4c1d233addf86c3273d56a03ea2a105a43546
184 Risk Score

Malware Insights

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

The PDF file contains a critical heuristic firing indicating a malicious redirector link. The embedded URL `https://crophysi.ru/strik?utm_term=irregular+past+tense+verbs+in+english` points to known malicious infrastructure. The ML classifier also strongly flagged this PDF as malicious. While no scripts were extracted, the presence of a malicious link strongly suggests a phishing or credential harvesting attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://crophysi.ru/strik?utm_term=irregular+past+tense+verbs+in+english In PDF document text
    • https://cdn-cms.f-static.net/uploads/4451374/normal_6041d98c18d15.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4427094/normal_6004317c51a61.pdfIn PDF document text
    • http://doriwev.iblogger.org/significance_of_genetic_code.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4483070/normal_605b92e0425a4.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4496824/normal_6021029173c88.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4419832/normal_5fc86623b50e6.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4472776/normal_5fcd0b9ebe926.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4478952/normal_5fdff1624d09e.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4476782/normal_604b18b55a518.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4417030/normal_6003e6ee2f0e2.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/178ac4f9-b20d-4f75-b7ba-efc70316056e/53876672545.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/28915644-02f7-4349-aee3-72eefabd3b55/wills_eye_new_jersey.pdfIn PDF document text
    • https://s3.amazonaws.com/kikunojulejuj/nz_ski_coronet_peak_snow_report.pdfIn PDF document text
    • http://bowubibegejojop.rf.gd/redojixuwikemi.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/05fb7794-5dad-471e-aedb-2a9f61241121/whirlpool_top_load_washer.pdfIn PDF document text
    • https://s3.amazonaws.com/vefagotoje/proform_505_cst_treadmill_weight_capacity.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/df7c1163-cb2a-4019-9128-0ce96be0dffb/the_vampire_diaries_quiz.pdfIn PDF document text
    • http://zadegijug.epizy.com/what_is_the_purpose_of_ode_to_a_nightingale.pdfIn PDF document text
    • https://s3.amazonaws.com/vavapekadoliti/18946818855.pdfIn PDF document text
    • http://dakonugubujom.rf.gd/good_qualities_of_a_manager.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/beb1a696-cec7-4abc-b6e7-0f607ffa8608/computer_hardware_and_networking_salary_in_india.pdfIn PDF document text
    • http://didaledagaxuz.rf.gd/kejenevivijewefodebipupu.pdfIn PDF document text
    • https://s3.amazonaws.com/wanalovum/wolinumaranupojak.pdfIn PDF document text
    • https://s3.amazonaws.com/visagogijulep/work_in_progress_report_construction.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_off0000e78f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE78F 5216 bytes
SHA-256: 570622b5cfd50052ed8790939cf9ab0ee79b38ea824498c4a98f4fcf94b380f1
font_01_sfnt_off0000f94b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF94B 10732 bytes
SHA-256: 1c25d610726aacde961d5a5b687c18935d8167bed0164e3e526e3d52aed60f65