Malicious PDF — malware analysis report

Static analysis result for SHA-256 3d3434758c90ec19…

MALICIOUS

PDF

77.2 KB Created: 2021-02-08 23:05:36 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: 7b844a0970e071bdd035c0e31b89ae02 SHA-1: 340593b7d0f64701d0a9b11cf268022cd95eb7fd SHA-256: 3d3434758c90ec19e356c738a751a943004ee6932cc9507bfd04e0be1d92eb49
244 Risk Score

Malware Insights

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

The PDF contains a large number of embedded links pointing to external PDF files, indicating it functions as a link farm. Several heuristics confirm this, including 'PDF_MALICIOUS_REDIRECTOR_LINK' and 'PDF_SEO_LINK_FARM'. The primary URL, 'https://crophysi.ru/wb?keyword=mcent%20browser%20apk%20mirror', suggests a lure related to mobile applications or potentially phishing. The sheer volume of links and the use of disposable hosting point towards an attempt to distribute malicious content or redirect users to phishing sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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.
  • 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/wb?keyword=mcent%20browser%20apk%20mirror In PDF document text
    • https://static.s123-cdn-static.com/uploads/4485821/normal_5fdfd47813e37.pdfIn PDF document text
    • https://cdn.sqhk.co/bovavadas/ibhfgi6/kijeko.pdfIn PDF document text
    • https://xefulexemifin.weebly.com/uploads/1/3/1/3/131398452/pudujoguzodufip.pdfIn PDF document text
    • https://cdn.sqhk.co/delobepaziw/ahdjiif/run_it_back_turbo_song_lyrics.pdfIn PDF document text
    • https://cdn.sqhk.co/kekotenonaxu/fhggjWp/4807915097.pdfIn PDF document text
    • http://fresh-ita.fun/656210409553wkpk.pdfIn PDF document text
    • https://pejadalat.weebly.com/uploads/1/3/0/7/130775017/gopap.pdfIn PDF document text
    • https://wimupajano.weebly.com/uploads/1/3/4/6/134682998/zeduloro_duwexug.pdfIn PDF document text
    • http://bitcoins-profits.com/xuzepowugugufemuywzr9.pdfIn PDF document text
    • https://raxiruzaxulam.weebly.com/uploads/1/3/0/7/130738564/bifosewajevaxixodoxi.pdfIn PDF document text
    • https://cdn.sqhk.co/gabisolovima/ge0Mgch/nidoxebugodofigufipokot.pdfIn PDF document text
    • https://cdn.sqhk.co/fedovipawe/ehgk0if/jobuzajuxubivopipuwagon.pdfIn PDF document text
    • https://xeludelibiw.weebly.com/uploads/1/3/4/3/134371965/322654.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4445557/normal_5fc86d6907f19.pdfIn PDF document text
    • https://cdn.sqhk.co/bofagenined/vDijjaQ/herpes_simplex_2_and_shingles_vaccine.pdfIn PDF document text
    • https://cdn.sqhk.co/jotenitix/iidha2B/3582325540.pdfIn PDF document text
    • https://cdn.sqhk.co/xixujipum/dztiduL/printable_large_print_word_search_for_seniors.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4407997/normal_5fd273f2f06c5.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
    • 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_off0000d9a7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9A7 5348 bytes
SHA-256: a8d45f04c5de958d3884763355c5c5c618e491860650ddb69ce432f7e2fe7f4b
font_01_sfnt_off0000ebde.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEBDE 11072 bytes
SHA-256: 2d31e0689341f023db4537727be44b33c8cd84060f19394824c69a9fcf2b4a4d
font_02_sfnt_off000111d0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111D0 16164 bytes
SHA-256: 6e3fbd491d8b71441998836ddca0d0c102716a221ea14f8143929167ad9a79b3