Malicious PDF — malware analysis report

Static analysis result for SHA-256 cd60a2a0e2f2915a…

MALICIOUS

PDF

69.8 KB Created: 2021-03-14 14:36:23 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: e62ba7f98169400d4e61593f27a63654 SHA-1: 9eb594146f70bfbf195ae266ac95942ab4925311 SHA-256: cd60a2a0e2f2915a1a8d6103fafac94aaf6feded9c0aa6bbd9785b6c85577211
156 Risk Score

Malware Insights

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

The PDF document is identified as malicious by ML classifiers and ClamAV, with a critical heuristic detecting a large number of external PDF links. The document body, though heavily obfuscated, suggests a lure related to a 'free physics textbook'. The primary malicious indicator is the extensive link farm, with one notable URL being https://botokaw.ru/strik?utm_term=libro+de+fisica+universitaria+13+edicion+pdf+gratis, which likely serves as a distribution point or part of a phishing campaign. While no scripts were explicitly extracted, the PDF format itself can embed JavaScript, and the heuristic 'PDF_SEO_LINK_FARM' indicates a deliberate attempt to manipulate search results or distribute further content.

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-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://botokaw.ru/strik?utm_term=libro+de+fisica+universitaria+13+edicion+pdf+gratis
    • https://cdn-cms.f-static.net/uploads/4420224/normal_600ecbbdf054b.pdf
    • http://wavesubikuviv.iblogger.org/rimegimiluzotikimodune.pdf
    • https://static.s123-cdn-static.com/uploads/4485591/normal_5ffc9bc98a899.pdf
    • https://static.s123-cdn-static.com/uploads/4489407/normal_5ff91bf06d44e.pdf
    • https://cdn-cms.f-static.net/uploads/4449406/normal_60365f2f68561.pdf
    • https://cdn-cms.f-static.net/uploads/4426677/normal_6017a356c50a1.pdf
    • http://kelirajisob.66ghz.com/93519423426.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/makixibawumebol/pigafugeditifoxu.pdf
    • https://s3.amazonaws.com/dejolavubukugeb/katun_love_song_video.pdf
    • https://uploads.strikinglycdn.com/files/8c5a2197-90b0-4de8-b9c2-6c78e0e2a111/13493625896.pdf
    • https://uploads.strikinglycdn.com/files/07f38947-0f5b-44b7-916b-ee9e90101c09/el_ser_y_la_nada_resumen.pdf
    • https://s3.amazonaws.com/tujeviwakirawu/pinixaguxeruw.pdf
    • https://s3.amazonaws.com/sowirutelevolur/bilderrahmen_groformat_holz.pdf
    • https://uploads.strikinglycdn.com/files/ff93a16e-1264-4ada-823b-6dc7989950f0/free_spanish_dictionary_app_for_iphone.pdf
    • http://zomudipanosu.epizy.com/hallelujah_salvation_and_glory_lyrics.pdf
    • https://s3.amazonaws.com/nodetuxapabara/1st_grade_math_curriculum_utah.pdf
    • https://98748e4b-3258-471a-903e-8ea98415cca0.filesusr.com/ugd/fd7405_5e8cf43b3b5a477b9cb18f33483fe653.pdf?index=true
    • https://469ee322-798e-4c1d-9571-af6764901f97.filesusr.com/ugd/57169b_3a62e5bc8a5f4dafa62fa70bb3f56a4d.pdf?index=true
    • https://bc732cde-fb09-4fee-8ab5-c82a45a1131b.filesusr.com/ugd/2ac701_1601455bc7ed444d871cf22f8be51aa7.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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d03c.bin
91daa99b0f55514f1d93aa7918ee0fa779a5a94025f85e302f3106065e7d975a		 pdf-font-stream PDF embedded font (sfnt) at offset 0xD03C 5648 bytes
font_01_sfnt_off0000e39a.bin
786399fef09ee201e65403aa97d3b1ba8dafbedb1e53b70d4ef24bfd7a029f4f		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE39A 11204 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.