Malicious PDF — malware analysis report

Static analysis result for SHA-256 646c7d4e18dfb8b3…

MALICIOUS

PDF

88.8 KB Created: 2021-06-10 20:21:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-23
MD5: 292d1a4e11dc0f339b0d0cd7913ef7f8 SHA-1: 6fc9799432f3e2416b5d311b00f19468f29488dd SHA-256: 646c7d4e18dfb8b3a9f4d00e634171837a942b0dd6671eebc88ed15544913b34
126 Risk Score

Malware Insights

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

The sample is a PDF file flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, with one prominent URL pointing to a suspicious domain ('krisoc.ru') that is likely part of a phishing or malware distribution scheme. The PDF structure and embedded content suggest it's designed to exploit users through deceptive links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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
  • 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://krisoc.ru/pbw?utm_term=distance+and+displacement+lab+activity+answers PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4479462/normal_5fe7055f63ba5.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4445104/normal_5fe70c0a94f19.pdfIn PDF document text
    • https://jesixuruforake.weebly.com/uploads/1/3/5/3/135328729/0c5e72f36.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4366367/normal_5ff3ff41ab136.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4447278/normal_5feba1087a70a.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4461207/normal_605bfbadb7093.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4453144/normal_601f2ca797a63.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4410020/normal_5fc68baa06472.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4421783/normal_6007ae96ab4c5.pdfIn PDF document text
    • https://derivasip.weebly.com/uploads/1/3/1/4/131407068/7612376.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4365606/normal_5fdc85e27c8da.pdfIn PDF document text
    • https://lafawifovetin.weebly.com/uploads/1/3/4/3/134369932/2461717.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://beratirupo.pbworks.com/w/file/fetch/144586950/59572549903.pdfIn PDF document text
    • http://rimikupababo.pbworks.com/f/jagiligexenoxuf.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/12e587c4-9446-444f-a63b-87356fca3fa8/how_to_set_my_sharp_atomic_clock.pdfIn PDF document text
    • http://venatulafiz.pbworks.com/w/file/fetch/145036827/61312219586.pdfIn PDF document text
    • http://zusemivak.pbworks.com/w/file/fetch/144676677/folamudesafuliziwud.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/087870f7-e67e-4d9b-a99a-5b636b7f71b9/cen-tech_cable_tracker_94181_manual.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/5ea6e014-8d90-45fe-8890-996235a849d2/the_road_cormac_mccarthy_genre.pdfIn PDF document text
    • http://lifuzopa.pbworks.com/w/file/fetch/144820158/46018734056.pdfIn PDF document text
    • http://viforepolu.pbworks.com/f/windows_xp_sp3_iso_usb_bootable.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_off00011d49.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11D49 5612 bytes
SHA-256: ac8ee94393d4d475be813134fd6bd4d8537f506ee1e0edb02ac5680e75000d14
font_01_sfnt_off00013064.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13064 10864 bytes
SHA-256: 0c9bef9c4cc4f3b02f397527a4b6d3009e9af28a4a4fd40c1cf9a80908838471

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