Malicious PDF — malware analysis report

Static analysis result for SHA-256 4a54d4765153805e…

MALICIOUS

PDF

76.9 KB Created: 2021-04-25 00:22:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 79c4d76cc6eae927d3098e046426bb1b SHA-1: 592cce35110a14522d6554219655043a4b16ab19 SHA-256: 4a54d4765153805e0c0649b13ef4d40a45692d5b4cd47610f81643132cb22ada
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many of which are to benign-looking documents, but one suspicious URL (https://jacksth.ru/strik?utm_term=how+to+remove+washing+machine+agitator) is present. The ClamAV detection and ML classifier strongly indicate malicious intent, likely related to phishing or malware distribution via the link farm. No scripts were extracted, but the PDF structure and numerous external links suggest an attempt to redirect the user to a malicious site.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

Heuristics 5

  • 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
  • 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://jacksth.ru/strik?utm_term=how+to+remove+washing+machine+agitator
    • https://cdn-cms.f-static.net/uploads/4444638/normal_60535853b1b9b.pdf
    • https://cdn-cms.f-static.net/uploads/4453342/normal_6034f20c656cf.pdf
    • https://cdn-cms.f-static.net/uploads/4449629/normal_600d6cdb30675.pdf
    • https://static.s123-cdn-static.com/uploads/4502439/normal_60083fde9b71a.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://6f465708-eb37-4ee2-8658-ebeec6cd93ea.filesusr.com/ugd/4bb103_da06199c5fea46f7951208bb95bab90f.pdf?index=true
    • http://jijomelaj.rf.gd/list_of_gazetted_holidays_2020_in_central_government.pdf
    • https://07e0a16e-b77d-475b-b724-88bbaedb347c.filesusr.com/ugd/8e9e2f_27051a2b2cd8403cb85731919b2526f0.pdf?index=true
    • https://s3.amazonaws.com/sigobija/blessed_are_you_lord_music_sheet.pdf
    • https://48e5b1ff-25fb-49a4-826b-3ad3f3a15688.filesusr.com/ugd/0d632a_04196cab152249c0b3dbadffae2db22d.pdf?index=true
    • https://uploads.strikinglycdn.com/files/150116db-330e-450c-abab-18b78585b629/delonghi_1500w_radia_s_oil_column_heater_with_timer_trrs0715e.g.pdf
    • https://s3.amazonaws.com/neviwove/31706429241.pdf
    • https://s3.amazonaws.com/nonabafat/dijovomovagu.pdf
    • https://488a161d-122f-4e25-b35e-34d1d0e27b34.filesusr.com/ugd/bbc910_d6e5ea757c19475c80b5603668fac234.pdf?index=true
    • https://s3.amazonaws.com/tikoweravisixu/61885483177.pdf
    • http://putudodizisag.epizy.com/gobad.pdf
    • https://9fc80a0e-b25b-4135-afeb-9811a1ea6bf8.filesusr.com/ugd/91e123_3fba5093a79a4b08b95337a771ab581f.pdf?index=true
    • https://uploads.strikinglycdn.com/files/53d0e7b0-65e2-4169-8f9b-a3d7ea8e7d6b/why_is_my_spectrum_remote_volume_not_working.pdf
    • https://uploads.strikinglycdn.com/files/fac21003-78cd-4cd6-9756-1cc1f3863e2f/how_to_fold_smart_trike_6_in_1.pdf
    • https://uploads.strikinglycdn.com/files/259a96df-4599-4caf-851c-78d2ea38aaca/learn_how_to_read_music_notes.pdf
    • https://535f918c-e50e-4760-9dbe-4b22a9cc1357.filesusr.com/ugd/65883d_4f50012cb38c4b3e8075ba0079655aee.pdf?index=true
    • https://f8ba888e-8f71-4fde-8303-550399648f4e.filesusr.com/ugd/17ce20_1f5238243acf48d9b8eed5c25e0f5bac.pdf?index=true
    • https://s3.amazonaws.com/naxizugenabi/aws_ec2_user_data_cloudformation.pdf
    • http://vubixijugisoloz.epizy.com/anatomy_books_for_mbbs.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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000eff4.bin
39c4c5c56a44cec76e101f663df40fb2f2167a45a0b1d098cc75d3bbe2e12d58		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEFF4 5292 bytes
font_01_sfnt_off000101e2.bin
cfbf55a926267b5ff5387cbae95dd934b476f9c6dbe7c1126497313cc59bf1cf		 pdf-font-stream PDF embedded font (sfnt) at offset 0x101E2 10508 bytes

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