Malicious PDF — malware analysis report

Static analysis result for SHA-256 b5888ecb261a6008…

MALICIOUS

PDF

72.6 KB Created: 2021-09-13 09:11:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 16de4050d67366c4f414c5504c1daa4c SHA-1: 99a1892ee7f13e39d9449a5af340189e0ca90a65 SHA-256: b5888ecb261a6008bb0510ea80e8eeae58cf9da7b7e6249aa37ef80041e597f8
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous embedded URLs pointing to various domains, many of which are associated with link farms and potentially compromised CMS uploads. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution via these links. No scripts were extracted, and the document body was unreadable, but the heuristic findings are sufficient to assess the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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 link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://synerhu.ru/uplcv?utm_term=airport+city+game+mod+apk PDF link annotation
    • http://thegioioto.store/upload/files/vefabiwizuwivigi.pdfIn PDF document text
    • http://sb-78.ru/files/file/pojozisuborapiwadusivo.pdfIn PDF document text
    • http://drairtools.com/ckfinder/userfiles/files/47674677928.pdfIn PDF document text
    • http://tichdiem.surecare.vn/uploads/userfiles/file/letevosubakiwud.pdfIn PDF document text
    • https://mysmartedu.com/uploadimages/files/kuvidiladeneminuzosakafe.pdfIn PDF document text
    • https://aldea.work/wp-content/plugins/super-forms/uploads/php/files/ad54ac11156811869d8465e47a0bff9e/33378801122.pdfIn PDF document text
    • http://www.tsahimmongol.com/uploads/images/files/robedes.pdfIn PDF document text
    • http://e-sportis.com/images/upload/gotawejatu.pdfIn PDF document text
    • https://plentis.eu/ckfinder/userfiles/files/37972824434.pdfIn PDF document text
    • http://dissanna.com/temp/fckeditor/file/53926698363.pdfIn PDF document text
    • https://waxparadise.pl/userfiles/file/79772218435.pdfIn PDF document text
    • https://dadesigning.com/daduserfiles/files/1888192041.pdfIn PDF document text
    • https://markzone.az/wp-content/plugins/super-forms/uploads/php/files/rhum89a7sr0h2mt3ls5kl3r9sj/dofojofufifegosumilivifiv.pdfIn PDF document text
    • http://www.guus.edu.mn/ckfinder/userfiles/files/mipeg.pdfIn PDF document text
    • http://technology-mp.it/userfiles/files/gosuba.pdfIn PDF document text
    • http://isleford.com/filespath/files/20210902115423.pdfIn PDF document text
    • http://sporteambiente.it/ckfinder/userfiles/files/nirogi.pdfIn PDF document text
    • http://bentleyplemtech.ru/userfiles/file/92604958058.pdfIn PDF document text
    • https://www.c2commercial.com/wp-content/plugins/super-forms/uploads/php/files/fcdffccbae95216290db121363d45bcf/toxukolezajumesigiwa.pdfIn PDF document text
    • http://irollee.com/userfiles/file/xavuvujofep.pdfIn PDF document text
    • https://ijfbacknumber.com/editor_up/savevefoduniron.pdfIn PDF document text
    • http://ersatzmonitor.de/userfiles/file/jetezonepoluk.pdfIn PDF document text
    • https://dbhattacharjee.com/ckfinder/userfiles/files/53847928784.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

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ba1e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBA1E 10728 bytes
SHA-256: 47b21f655dc4ad1655bd84ecb88cdd286c80f552a71a76393b691694f34eace2
font_01_sfnt_off0000d2a1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD2A1 16588 bytes
SHA-256: 085e86d3c343eba50cd6eeded5b94effd1bfb3046b7d849cf361a1c2094465be
font_02_sfnt_off0000fd36.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD36 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1