Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8a43ef20cb9a401…

MALICIOUS

PDF

88.0 KB Created: 2021-03-23 01:54:06 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: b95b9773bffe8bc0d642e665170b9d2f SHA-1: 7c4ff4e21ed5c0a96966e0a56a0ebf339600d33e SHA-256: a8a43ef20cb9a40150b36162fca7bc7be8277115e94c048a4ce6d0923f620f68
164 Risk Score

Malware Insights

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

The sample is a malicious PDF identified by ML classifiers and ClamAV as a phishing trojan. It contains numerous external links, including one with a keyword suggesting it's part of an SEO link farm designed to attract unsuspecting users. The presence of embedded URLs and the 'Fake invoice / payment lure' heuristic indicate a phishing or social engineering attempt to trick users into clicking malicious links.

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-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Fake invoice / payment lure low SE_INVOICE_LURE
    Document contains invoice or payment language paired with an action verb — useful context when combined with link, macro, or attachment indicators
  • 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://druttle.ru/wix?keyword=instructional+manual+template+word
    • https://cdn.sqhk.co/xusopusavo/fjbhhje/assistant_shortcuts_app.pdf
    • https://cdn.sqhk.co/ferobisuw/hiazjbY/ximururerin.pdf
    • https://cdn.sqhk.co/wemulekojex/fhhigij/kuwinevipup.pdf
    • https://cdn.sqhk.co/waxobakal/agd47id/vector_definition_molecular_biology.pdf
    • https://cdn-cms.f-static.net/uploads/4484990/normal_601da5c447e84.pdf
    • https://static.s123-cdn-static.com/uploads/4455657/normal_5fe497058c27d.pdf
    • https://static.s123-cdn-static.com/uploads/4444366/normal_5fc6935b5abcb.pdf
    • https://cdn.sqhk.co/felebamifuk/Iiix3dE/foxebebugez.pdf
    • http://kanubanedagag.22web.org/pojekomobimonum.pdf
    • https://cdn-cms.f-static.net/uploads/4390637/normal_6050423ac8ab9.pdf
    • https://cdn-cms.f-static.net/uploads/4490365/normal_60427103957b0.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://ff4d9611-e7ea-45f2-85d3-f0b464ef817f.filesusr.com/ugd/48f461_1d2834bf59dc4937a48c49affac650dc.pdf?index=true
    • https://69df74eb-9f83-488d-97bb-abb55063df61.filesusr.com/ugd/f34323_425d9a619443417e9c61b76dfc6aa565.pdf?index=true
    • https://19527f6f-7821-4b33-8e58-d909ab9a203f.filesusr.com/ugd/b18fc6_5b617e7ba3ad41b4a87084ab574ab96c.pdf?index=true
    • http://mezezix.rf.gd/windows_10_bootable_iso_creator_free.pdf
    • https://5a20c861-23fd-468b-888e-078c5342874f.filesusr.com/ugd/924841_c3d14d7968034aef85e43b5e1c5d02f4.pdf?index=true
    • https://0eb00d84-361a-45dc-b346-1af5c8eb785c.filesusr.com/ugd/d79848_f017f89a8c564639bcae47b70a9cd60b.pdf?index=true
    • http://kaderuzaxaje.rf.gd/swann_8_camera_wireless_system.pdf
    • https://b064d0e4-88d6-4b7e-8087-8ebf790fcba6.filesusr.com/ugd/ca32a8_4e2a730852f34d169f176fbf04b2ca7e.pdf?index=true
    • https://a9f3490c-def6-45ea-9957-aefa341d54bd.filesusr.com/ugd/84b587_0a774fd66aee4c6789ba7eefcabd5c54.pdf?index=true
    • https://d4f4546a-a836-4b3d-8651-c56b89608eca.filesusr.com/ugd/3e9e83_d7c84b5cc73e48f7855fdc28ae24c9df.pdf?index=true
    • http://wedofisirix.epizy.com/tratamiento_desequilibrio_acido_base.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_off00011ad5.bin
46463dd0cf028a0a0403517062a71443e1d2cb55c40b9474909075310cc7b4e5		 pdf-font-stream PDF embedded font (sfnt) at offset 0x11AD5 5248 bytes
font_01_sfnt_off00012ca8.bin
03abb3815502b9e5469d8d94df4f93c383e6207e0b13833474cd32577a1af15f		 pdf-font-stream PDF embedded font (sfnt) at offset 0x12CA8 11288 bytes

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