Malicious PDF — malware analysis report

Static analysis result for SHA-256 81276dd9c636a496…

MALICIOUS

PDF

82.9 KB Created: 2021-09-17 17:48:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 897ac061483c5c7b77f2921ffa9a0f93 SHA-1: d6f8cd292a2af49320c91fa994a6858ffe7138dd SHA-256: 81276dd9c636a496c53167524e463e536febcd5be4ca9f79b491e181e6e1fb15
156 Risk Score

Malware Insights

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

This PDF file was identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It functions as a link farm, with numerous embedded URLs pointing to compromised websites, likely to lure users into phishing scams or download further malware. The presence of multiple distinct hosts and the use of 'utm_term' parameters suggest a coordinated effort to distribute malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

Heuristics 6

  • 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 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://krisoc.ru/uplcv?utm_term=soft+reset+android PDF link annotation
    • https://herfection.herfection.tw/upload/ckfinder_temp/files/20210908065641.pdfIn PDF document text
    • https://yidinfo.net/wp-content/plugins/super-forms/uploads/php/files/u9emmk5bf8k3h5s01kq9t9fq6i/majizejilu.pdfIn PDF document text
    • https://voicelux.ru/wp-content/plugins/super-forms/uploads/php/files/5362f30a40863d63afd2cf029d5faa96/13466934801.pdfIn PDF document text
    • https://matraci.info/UserFiles/File/75461237652.pdfIn PDF document text
    • https://wendi101.com/userfiles/file/60225756111.pdfIn PDF document text
    • https://rgcsmt.org/ckfinder/userfiles/files/supekuwexitasikajemile.pdfIn PDF document text
    • http://bkm-market.net/userfiles/file/64535363030.pdfIn PDF document text
    • http://kuryakyn.ru/userfiles/file/bunidemufonibukede.pdfIn PDF document text
    • http://ekorepetycje.eu/Upload/file/vorebadidelukelo.pdfIn PDF document text
    • https://jkmart.net/FCKFiles/File/63319024597.pdfIn PDF document text
    • http://yuc-fac.com/uploadfiles/20210903125518.pdfIn PDF document text
    • http://daiichibus.vn/uploads/news_file/giwilug.pdfIn PDF document text
    • https://halobysciton.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d29c266865---nimodoporumafivutuzusop.pdfIn PDF document text
    • http://madang.eu/f_pds/fck/file/88612817067.pdfIn PDF document text
    • http://renovfab-menuiserie.com/userfiles/file/mavom.pdfIn PDF document text
    • https://www.aironface.com/wp-content/plugins/super-forms/uploads/php/files/c5ec0dc90b818264282e7e81caa470b3/barovurivejatabulubiweme.pdfIn PDF document text
    • http://etasystem.net/userfiles/files/titatanog.pdfIn PDF document text
    • http://st-johnson.com/Uploadfiles/files/rufizisaxuzavadavijepa.pdfIn PDF document text
    • http://taiwan-casters.com/userfiles/file/42820851267.pdfIn PDF document text
    • http://styrexon.cz/userfiles/file/41386106816.pdfIn PDF document text
    • http://www.louthadventures.ie/wp-content/plugins/formcraft/file-upload/server/content/files/16136909d6afbc---suluxonenini.pdfIn PDF document text
    • http://kindervakantieweekdeurne.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613a0b16cf626---10157476756.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_off0000e11b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE11B 10376 bytes
SHA-256: b9757effa8b8bbff0b1d50cca525f8c955db77ad5cfcb1b9654bfed7b2904f3f
font_01_sfnt_off0000f8ab.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF8AB 18048 bytes
SHA-256: 36fd6ffe9007001b8d23e2083021cd5934c749b5930f0cf2c539abe99776a849
font_02_sfnt_off000126e0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x126E0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1