Malicious PDF — malware analysis report

Static analysis result for SHA-256 1a81137fce4b7b98…

MALICIOUS

PDF

77.7 KB Created: 2021-01-06 08:32:55 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-25
MD5: be6a6f617f6546832aebfcbcfa047f1b SHA-1: d27cc3058ed55a3efb2a6c0f7565a843fc10053e SHA-256: 1a81137fce4b7b98db42bc9117fe090b678a18d1421c0bd24028d88681a77e07
302 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript T1203 Exploitation for Client Execution

This PDF document exhibits multiple indicators of malicious activity, including links to known malicious redirectors and a large number of embedded PDF links, suggesting a link farm for SEO manipulation. The presence of a 'download button' lure and a 'browser extension installation lure' strongly indicates a social engineering attempt to trick the user into downloading potentially malicious content. The ML classifier and ClamAV detection further support its malicious classification.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 8

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 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.
  • Image lure linking to an SEO redirector (free-download phishing) high PDF_SEO_UTM_REDIRECTOR_LINK
    PDF embeds an image with little or no body text and a clickable link to a multi-word utm_term / FeedBurner-proxied SEO redirector — the 'free ebook / solution-manual / document download' phishing family that ranks for natural-language search queries and routes the user into a payload/redirect chain. The PDF carries no exploit; the risk is the linked destination. Flagged structurally (image lure + SEO redirector) so it does not depend on a ClamAV/ML signature, and regardless of how many filler text pages the lure carries.
  • Browser extension / update installation lure high SE_BROWSER_INSTALL_LURE
    Document tells the user to install a browser extension, plugin, viewer, or browser update to view content — a common social-engineering path for credential theft and malware installation
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://traffking.ru/aws?utm_term=free+avg+internet+security+antivirus+software In PDF document text
    • https://cdn-cms.f-static.net/uploads/4494648/normal_5fd6c43ab3c27.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4474462/normal_5fcf3de342c98.pdfIn PDF document text
    • https://toxujubew.weebly.com/uploads/1/3/1/4/131437446/cf97807.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4469386/normal_5fd999fbe1ca4.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4382976/normal_5ff018eadaffb.pdfIn PDF document text
    • https://noxepelobisuse.weebly.com/uploads/1/3/1/8/131871648/1893818.pdfIn PDF document text
    • https://fukobararusi.weebly.com/uploads/1/3/4/4/134404541/kofefuvijiritipev.pdfIn PDF document text
    • https://gomigara.weebly.com/uploads/1/3/4/7/134727279/f2f924fbbeff4a2.pdfIn PDF document text
    • https://tokemenar.weebly.com/uploads/1/3/4/3/134337898/1793766.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4469630/normal_5ff391fe8417d.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4369768/normal_5fd0a5aad93b2.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f587.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF587 5224 bytes
SHA-256: e1fd3f329b7701b3790c5862240b966b9f2ac1c7bed3f98cded8b5a64ab5bc1a
font_01_sfnt_off00010783.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10783 10128 bytes
SHA-256: 6e6b57a900aea3ffbd6ef4bc22bee34d2e8923ae4e389809b9052199103342d2

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