Malicious PDF — malware analysis report

Static analysis result for SHA-256 f23fb96ce80a2a7e…

MALICIOUS

PDF

79.4 KB Created: 2021-05-24 00:26:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 99ef237ce0ab0696df6ef7567d2d104f SHA-1: 85bf2fcef67cf71ccbde88b8fecc82d4ad0af6ac SHA-256: f23fb96ce80a2a7e15ae9954d04e5ca82e221cc5d240b255ee4a066617f9c420
156 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The presence of a large number of external links, many pointing to PDF files hosted on file-sharing services, suggests a link farm or a distribution mechanism for further payloads. While no scripts were explicitly extracted, the PDF structure and the heuristic firings point towards a phishing or malware distribution scheme.

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://rasiguxi.weebly.com/uploads/1/3/5/3/135314707/08fdd3b4972.pdf
    • https://cdn-cms.f-static.net/uploads/4374372/normal_60418c3459b08.pdf
    • https://telidububiz.weebly.com/uploads/1/3/1/4/131452987/mawuxamununuf.pdf
    • https://cdn-cms.f-static.net/uploads/4375353/normal_605bb984ca28a.pdf
    • https://static.s123-cdn-static.com/uploads/4421613/normal_5fef1b7806e81.pdf
    • https://cdn-cms.f-static.net/uploads/4450732/normal_606578baa8cea.pdf
    • https://cdn-cms.f-static.net/uploads/4455185/normal_60143cf5457b0.pdf
    • https://vufizirisabewi.weebly.com/uploads/1/3/4/4/134443644/zavufa.pdf
    • https://cdn-cms.f-static.net/uploads/4451566/normal_6034a00b41cd3.pdf
    • https://cdn-cms.f-static.net/uploads/4366313/normal_6044fcdcef319.pdf
    • https://cdn-cms.f-static.net/uploads/4417207/normal_6054e7824c490.pdf
    • https://static.s123-cdn-static.com/uploads/4379477/normal_5ff38deef17e4.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://feedproxy.google.com/~r/wb/ENAH/~3/Xr6F2PkPTcg/wb?keyword=carson%20dellosa%20answer%20key%20grade%205
    • https://s3.amazonaws.com/rezugekolaba/what_are_1nf_2nf_and_3nf.pdf
    • https://s3.amazonaws.com/siwixomudit/channa_mereya_lyrics_video_song_free.pdf
    • https://uploads.strikinglycdn.com/files/f190709d-b3f1-4db4-b996-ad2e0d27c92a/disoluramuxubolozudamam.pdf
    • https://uploads.strikinglycdn.com/files/005aa463-82cc-4817-b479-827078e2f3f8/4241637583.pdf
    • https://uploads.strikinglycdn.com/files/f760c1ca-840f-4de1-99bb-01bc579c0933/how_to_draw_a_turkey_stack_folding_surprise.pdf
    • https://s3.amazonaws.com/jiwisi/nelitigat.pdf
    • https://uploads.strikinglycdn.com/files/6079e2eb-5b22-4a4b-a816-80d9d33853ae/best_online_booking_app.pdf
    • https://uploads.strikinglycdn.com/files/40183f19-b6a0-4c93-94c4-ea805cf1e8d4/37178267934.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_off0000f722.bin
c4da0e622d6d60c1dc01eae32c841583bcbe5464dc8cf284de1dfd249350832b
pdf-font-stream PDF embedded font (sfnt) at offset 0xF722 5280 bytes
font_01_sfnt_off00010941.bin
b6fb99c610f801021cc62f501c10209397bcdc15d3fa8debb69dcc5d7625e1dd
pdf-font-stream PDF embedded font (sfnt) at offset 0x10941 11508 bytes