Malicious PDF — malware analysis report

Static analysis result for SHA-256 ec8838846ccd7372…

MALICIOUS

PDF

87.9 KB Created: 2021-02-24 13:13:52 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: 5dc792c3b7ea810dd6923ff5c8af19e0 SHA-1: c2dc38a731af89da7fdcf6894b5d355cbebe8521 SHA-256: ec8838846ccd7372a0d4c58c5603315ea05484fcb1780d12d6fd167ff77b2c83
184 Risk Score

Malware Insights

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

The sample is a PDF document flagged by multiple heuristics as malicious, including a critical alert for linking to known malicious redirector infrastructure. The ML classifier also assigned a high probability of maliciousness. The document body is heavily obfuscated and unreadable, but the presence of embedded URLs and the PDF_MALICIOUS_REDIRECTOR_LINK heuristic strongly suggest the intent is to redirect the user to a malicious site, likely for phishing or to download further malware. No scripts were extracted, but the PDF structure itself facilitates the malicious redirection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9984

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
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://crophysi.ru/wix?keyword=square+terracotta+pots+b%2526q In PDF document text
    • https://static.s123-cdn-static.com/uploads/4455672/normal_60001675ce797.pdfIn PDF document text
    • https://cdn.sqhk.co/murefazomejo/ibQ8ihM/mafaxasomirufetepinefovun.pdfIn PDF document text
    • http://sdfsdfsdf.shaketorch.com/vefikasetifolebojuw.pdfIn PDF document text
    • http://divoposolabuv.22web.org/21087794771.pdfIn PDF document text
    • https://cdn.sqhk.co/lexaxemiji/iggdXGr/oregon_ohio_cop_shooting.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4369654/normal_6021a35a529db.pdfIn PDF document text
    • https://cdn.sqhk.co/tokofape/htgjBsp/xelapavew.pdfIn PDF document text
    • https://cdn.sqhk.co/xijodepub/dhhiehh/pidugavovokukuso.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4444386/normal_600f02fe54a53.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://fotafufoka.epizy.com/gotewudo.pdfIn PDF document text
    • http://rupegofiminatef.epizy.com/bluebook_short_form_case_cite.pdfIn PDF document text
    • http://worizekadi.epizy.com/38095262662.pdfIn PDF document text
    • https://s3.amazonaws.com/divelatoxa/what_does_stability_control_do_on_a_car.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://scripts.sil.org/OFLIn PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00010b87.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B87 4064 bytes
SHA-256: eaee2c0cbdf0237dd883e89955366c5aaebbed6d3db139197b6ee8fb44246366
font_01_sfnt_off00011955.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11955 10984 bytes
SHA-256: ca4b681c78ac2d0c578087eb2b6a843e81d9e89033cd8078e943f06a8b48eb95
font_02_sfnt_off00013f20.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13F20 16164 bytes
SHA-256: c41fc46809d2260d2d1a821cef6bb00dae560fdbad380da94a93f29d012df54e

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