Malicious PDF — malware analysis report

Static analysis result for SHA-256 1881bb8d356519f8…

MALICIOUS

PDF

76.7 KB Created: 2021-04-26 09:33:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: e96c59f93c0e2436b9d4c74b19a2755e SHA-1: 309c6e44f5c0b5ba4c8ba837181331d79e24d09a SHA-256: 1881bb8d356519f896387160f51e1041f8c92aec1671ebd5851ca1bc0eaffe14
126 Risk Score

Malware Insights

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

The file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. The PDF contains numerous embedded URLs, many pointing to unknown or suspicious domains, suggesting it functions as a link farm or phishing lure. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' specifically flags this behavior, indicating an attempt to obscure malicious links within a large number of seemingly legitimate but disposable domains.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9995

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://www.enwidth.com/sites/default/files/webform/resumes/zozagosetimof.pdf In PDF document text
    • http://www.sumnercountyhospital.org/sites/default/files/webform/xubapubawaral.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/kepasibadugemefobovabo.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/1289321409.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/xugapovapoz.pdfIn PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/powevalixerofewum.pdfIn PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/87400145234.pdfIn PDF document text
    • https://aboss.by/sites/default/files/webform/zivexovoburowunaxomenip.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/51762260361.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/Om9ozkHLxGw/uplcv?utm_term=samsung+n5300+weightPDF link annotation
    • https://ec.europa.eu/eip/agriculture/sites/default/files/webform/zuwamusijugowop.pdfIn PDF document text
    • https://ec.europa.eu/eip/agriculture/sites/default/files/webform/72323592377.pdfIn PDF document text
    • https://www.vub.be/sites/vub/files/webform/piwolumubixu.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_004_off000102a4.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x102A4 16244 bytes
SHA-256: ffb29593d493139470443d7ece1f5a618f2895ce395a8f9e0bc7a8a58b8a1a97
font_00_sfnt_off0000c323.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC323 5368 bytes
SHA-256: 9487d2c7806045b6d3b8337adbb8c698d2363633ec2c37b2e4ba716320edc336
font_01_sfnt_off0000d541.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD541 14380 bytes
SHA-256: e82d499c912d3edd586b6f9a52908b47ac7ebc7d7e2a0db43596a4f675505d1c
font_03_sfnt_off00011815.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11815 4324 bytes
SHA-256: b50a2106bf82917db0cd3cf88f63c5e8cc3298b343ace5cffc591b35df33d24c

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