Malicious PDF — malware analysis report

Static analysis result for SHA-256 a37319f9ec2f4441…

MALICIOUS

PDF

77.7 KB Created: 2021-06-06 20:41:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 71f3a7091fdad2c97c0c9ff557504cbb SHA-1: 7e109ddd97508bcb406d208a9cc7e31961480e8d SHA-256: a37319f9ec2f444129d6b138770d6abcffcba0754fda2ac669b5b96decf7c855
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 pointing to seemingly unrelated documents, which is indicative of a link farm or SEO poisoning technique. The ClamAV detection and ML classifier strongly suggest malicious intent, likely related to phishing or malware distribution via the embedded URLs. No scripts were extracted, but the PDF structure itself is being leveraged to redirect users.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://jottigo.ru/123?utm_term=balao+da+informatica+jundiai
    • https://berizekaxijaj.weebly.com/uploads/1/3/4/5/134501449/napunusogajabi-kofepiri.pdf
    • https://cdn-cms.f-static.net/uploads/4459165/normal_604e91a7b7eaa.pdf
    • https://wotafoxig.weebly.com/uploads/1/3/4/3/134306194/8803690.pdf
    • https://pirebuvix.weebly.com/uploads/1/3/2/7/132710697/c9faf61a1.pdf
    • https://cdn-cms.f-static.net/uploads/4459055/normal_5fea0fb8e6e41.pdf
    • https://puxipevabama.weebly.com/uploads/1/3/4/3/134308905/a43163a32881a95.pdf
    • https://fuwidomanajano.weebly.com/uploads/1/3/0/8/130874101/4309589.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.daltonmaag.com/
    • https://uploads.strikinglycdn.com/files/527930f0-8372-4cfd-a9f6-a0ac86ca47f5/control_systems_engineering_7th_edition_solutions.pdf
    • http://jilawuxifi.pbworks.com/w/file/fetch/144659286/how_to_get_a_snapped_key_out_of_a_car_ignition.pdf
    • http://zapibibilubo.pbworks.com/f/42467916754.pdf
    • http://sazupamufode.pbworks.com/w/file/fetch/144450414/wixeveledetopozaruxulevo.pdf
    • http://juvupumanut.pbworks.com/f/tufiv.pdf
    • https://uploads.strikinglycdn.com/files/26b71240-5082-4e12-99ef-200ccd070fe2/ravun.pdf
    • https://uploads.strikinglycdn.com/files/005272d6-e57b-40b5-9625-9a2fc7b60112/4172978138.pdf
    • http://nubuzefi.pbworks.com/f/97577307023.pdf
    • https://uploads.strikinglycdn.com/files/fc3fbc34-94df-4ccc-aa12-bd1633f229cc/dios_sea_exaltado_marcos_witt_letra.pdf
    • http://saladolu.pbworks.com/w/file/fetch/144684240/74115808827.pdf
    • https://uploads.strikinglycdn.com/files/4b305afc-ca14-4f12-8a1f-53cea547ad44/king_arthur_and_the_knights_of_the_round_table_movie_wiki.pdf
    • https://uploads.strikinglycdn.com/files/d9d1dcc9-5631-42bb-8c24-0e5cd836d0bd/32494382160.pdf
    • https://uploads.strikinglycdn.com/files/ed7634fa-8d47-47f9-933b-da81c99d6f49/world_remit_bank_transfer_south_africa.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e112.bin
7dcf4f71505a4a9873325a47d87b558002cde63495ad9a3255be8845a7e277f3
pdf-font-stream PDF embedded font (sfnt) at offset 0xE112 4880 bytes
font_01_sfnt_off0000f180.bin
1cce282cb2151a2048dee8194bc27776fd2cd9f1ccb3d919aebe9b0e3926e2eb
pdf-font-stream PDF embedded font (sfnt) at offset 0xF180 13076 bytes
font_02_sfnt_off00011a04.bin
d1f4a20f0e35a0564be54678b929bb8c711862c507f070c2b9a6abea8daf4378
pdf-font-stream PDF embedded font (sfnt) at offset 0x11A04 4324 bytes