Malicious PDF — malware analysis report

Static analysis result for SHA-256 516c9e5aa10d47cc…

MALICIOUS

PDF

72.7 KB Created: 2021-03-28 14:08:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: b66da554b3f348327f8babf102fe4279 SHA-1: 664eb1577ce864cac01b13338e1a381fbf0476f7 SHA-256: 516c9e5aa10d47ccad062f8abef23a564eb227573538cd32817f3dcca04cee1b
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 of which are disguised as academic paper search results, indicating a link farm or phishing attempt. The ClamAV detection and ML classifier strongly suggest malicious intent, likely to redirect users to malicious sites for phishing or malware delivery. No scripts were extracted, but the PDF structure itself is used to host numerous URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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://xezojetit.ru/123?utm_term=microfacies+of+carbonate+rocks+pdf
    • https://cdn-cms.f-static.net/uploads/4458163/normal_60519418b395f.pdf
    • https://cdn.sqhk.co/forokuxodel/cgAghid/english_audio_songs_with_lyrics_free_download.pdf
    • https://cdn-cms.f-static.net/uploads/4370317/normal_6050b7471c5b7.pdf
    • https://cdn-cms.f-static.net/uploads/4419626/normal_60313573b1791.pdf
    • https://cdn-cms.f-static.net/uploads/4405639/normal_6043ddf0cc760.pdf
    • https://cdn-cms.f-static.net/uploads/4443617/normal_6035fa7dbdb74.pdf
    • https://cdn-cms.f-static.net/uploads/4484815/normal_603accde3b2a1.pdf
    • https://cdn.sqhk.co/xivovido/gjuYlYP/tm_prepaid_internet_promos_2019.pdf
    • https://cdn-cms.f-static.net/uploads/4529087/normal_5fd5f4e01015b.pdf
    • https://cdn.sqhk.co/tofegejij/jheghhd/custom_stickers_made_in_usa.pdf
    • https://cdn-cms.f-static.net/uploads/4443325/normal_6019842fc1ffb.pdf
    • https://cdn-cms.f-static.net/uploads/4474978/normal_5fd3d7fa54b6d.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/145f3ab1-9fc8-4d34-a3ec-39538f822f26/sharp_portable_air_conditioner_replacement_parts.pdf
    • https://27475d5a-2981-497d-8cd5-0c310ef10f8b.filesusr.com/ugd/9cb927_c50cd774051940728b5de503733f89c8.pdf?index=true
    • https://40ba1f7a-6e91-49bb-bbb8-dfbb40a2bc60.filesusr.com/ugd/22bf55_f296efb49ab44768a287ab2b19ffff82.pdf?index=true
    • https://s3.amazonaws.com/xufaxoferugod/59845103169.pdf
    • https://s3.amazonaws.com/tiduro/pibefojuwefana.pdf
    • https://uploads.strikinglycdn.com/files/99701102-778f-4cb3-a065-910e14942628/what_does_irishman_mean.pdf
    • https://9305c775-266c-4126-9ef9-90a5cffee957.filesusr.com/ugd/c3f88d_6f1e5dd766b74eedba2d59881c365800.pdf?index=true
    • https://uploads.strikinglycdn.com/files/e249d4c7-88d0-4665-98a3-34b4127c8c8e/spektrum_dx7_factory_reset.pdf
    • https://s3.amazonaws.com/kibavutibeved/apollo_twin_duo_usb3_audio_interface_for_pc.pdf
    • https://uploads.strikinglycdn.com/files/4d0f4e1f-7fe5-4984-988a-7a99ad0d46b9/zirivuvebudalumulumemut.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_off0000dd74.bin
e0a33d17367895a6dde8eefb43d90ea820a95fe86ddd1b101b2f7a9c664b8d16
pdf-font-stream PDF embedded font (sfnt) at offset 0xDD74 5324 bytes
font_01_sfnt_off0000efa8.bin
180366c163a86e2b88bfbd1621458f33ce38606216534bc59c479c8d3703d314
pdf-font-stream PDF embedded font (sfnt) at offset 0xEFA8 11084 bytes