Malicious PDF — malware analysis report

Static analysis result for SHA-256 fc8ad0fb54c63467…

MALICIOUS

PDF

76.0 KB Created: 2021-05-08 14:08:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 5f8179c1b7190786032ae09f4058766f SHA-1: bf833ad0cee7aa7814772c9e6b083e3ef779fe7d SHA-256: fc8ad0fb54c634679483c161b6d62836dc89c99b82f382b3bd187365a8f7e816
156 Risk Score

Malware Insights

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

This PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and a machine learning classifier indicated a high probability of maliciousness. It contains a large number of external links, characteristic of a link farm, with a primary suspicious URL being https://jacksth.ru/strik. The document body, though heavily obfuscated, suggests a lure related to "Theory u book", aligning with phishing or scam tactics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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=theory+u+book
    • http://xufuxenu.mypressonline.com/fevodarabar.pdf
    • http://pigalimiru.medianewsonline.com/2610327854.pdf
    • https://cdn-cms.f-static.net/uploads/4404310/normal_6048258f9af21.pdf
    • https://cdn-cms.f-static.net/uploads/4372371/normal_5fea21f615daf.pdf
    • http://bobujopolodusol.mygamesonline.org/35239867018.pdf
    • http://laribij.scienceontheweb.net/centralisation_and_decentralisation_in_public_administration.pdf
    • https://cdn-cms.f-static.net/uploads/4489977/normal_5fdba1ffde210.pdf
    • https://static.s123-cdn-static.com/uploads/4475204/normal_5fffbf26a979a.pdf
    • https://cdn-cms.f-static.net/uploads/4417815/normal_603286a932ef5.pdf
    • https://cdn-cms.f-static.net/uploads/4419206/normal_606bdef28ecd9.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.daltonmaag.com/
    • https://uploads.strikinglycdn.com/files/af7ab472-6906-420a-9929-96cb12fb2b23/98790365690.pdf
    • http://naxefugoxodikow.atwebpages.com/xefotuvogo.pdf
    • http://zapusov.atwebpages.com/cessione_del_credito_carrozzeria.pdf
    • https://uploads.strikinglycdn.com/files/fd13a60e-984c-46c8-ba09-e5382aab3daa/genius_loci_towards_a_phenomenology_of_architecture_espaol.pdf
    • https://a98f38e8-5810-4fc9-be6a-c3d78c7c4f9f.filesusr.com/ugd/921909_77dab40c0ece4904a336ff24ea1ef434.pdf?index=true
    • https://uploads.strikinglycdn.com/files/ff683566-1943-4216-8bae-f6a2e1231290/gigixi.pdf
    • https://d12d056d-c16f-42d2-bb36-b12dbd13f8e5.filesusr.com/ugd/a2005d_f0bb11508a0d4bdeb654ea16ffe7cb1d.pdf?index=true
    • 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_off0000e300.bin
82c1731b03f9c4ef5985d282f5c4e6008bdcfb6ce4b54395c315a3f085bcbcb1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE300 4256 bytes
font_01_sfnt_off0000f17e.bin
c4a6d9d613707a1009a8e8e13842a4b41cbc3ada2ec2876e7659bf3356141b7f		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF17E 10440 bytes
font_02_sfnt_off00011503.bin
0d0f64e27578eb124b8bc81c7eceacdd166e22eddd95c81328e9fbd7de2a6333		 pdf-font-stream PDF embedded font (sfnt) at offset 0x11503 4324 bytes

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