Malicious PDF — malware analysis report

Static analysis result for SHA-256 8de6639ff59693e1…

MALICIOUS

PDF

85.4 KB Created: 2021-09-20 03:02:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 58df2eed232f541899d0b8138ea3a115 SHA-1: 997412b1973ca5b5872b07106a183bbea71f0b5f SHA-256: 8de6639ff59693e1e44b8fb98f2447582b5e3bc95281f5b27ee7381013c6b757
156 Risk Score

Malware Insights

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

The file is identified as malicious by ClamAV and an ML classifier, exhibiting characteristics of a link farm. Multiple heuristics indicate the PDF contains numerous external URIs, many pointing to compromised CMS uploads or disposable hosting. The document body is heavily obfuscated, preventing analysis of its direct content, but the overall structure and heuristic firings suggest a malicious intent to redirect users through a series of links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 http://tnslib.su/userfiles/files/konodedesukijidi.pdf In PDF document text
    • http://toyteepee.com/uploadfiles/file/210915145524473678ev2tap.pdfIn PDF document text
    • http://geoman.cz/data/file/69654342115.pdfIn PDF document text
    • http://pieseclimaauto.com/files/file/55556427248.pdfIn PDF document text
    • http://onestep-tokyo.com/userfiles/file/laxijorilusuxiser.pdfIn PDF document text
    • http://szpk.hu/_user/file/60341740739.pdfIn PDF document text
    • https://ycb.one/pro_pic/files/61551493127.pdfIn PDF document text
    • http://www.oneworldkarate.com/fckeditorimages/userfiles/file/26761141847.pdfIn PDF document text
    • http://www.consorcio.edu.pe/wp-content/plugins/formcraft/file-upload/server/content/files/1612f1386d8f1d---rojepozuvasip.pdfIn PDF document text
    • http://radio-salsa.fr/php/rs/filesupload/file/74219082104.pdfIn PDF document text
    • https://doitsolutions.co/wp-content/plugins/super-forms/uploads/php/files/f53e983f393bea1b65fe54c0bedcd995/31730920368.pdfIn PDF document text
    • https://www.kiakaha.gr/wp-content/plugins/super-forms/uploads/php/files/b4ncihjhcmitpbvbr6ph6r81rc/65767859293.pdfIn PDF document text
    • http://tochalco.com/uploads/files/xodivoberutegeripuvoxi.pdfIn PDF document text
    • http://kimsanghun.com/upload/userfiles/file/2021962135208196.pdfIn PDF document text
    • https://goldfieldssanddrags.com.au/ckfinder/userfiles/files/1946454839.pdfIn PDF document text
    • http://aiswaryamatrimonials.com/fck_uploads/file/88251103546.pdfIn PDF document text
    • http://herborgthailand.com/file_media/file_image/file/97063393761.pdfIn PDF document text
    • https://ntct-dz.com/ckfinder/userfiles/files/gadumedoviruzifibakasiwu.pdfIn PDF document text
    • https://ccaquebec.com/userupload/files/79296319378.pdfIn PDF document text
    • http://bbfrontedelmare.com/userfiles/files/1985921544.pdfIn PDF document text
    • https://vcvscr.cz/www/www/fckphotos/file/45774899225.pdfIn PDF document text
    • https://wacee.net/wp-content/plugins/formcraft/file-upload/server/content/files/1613c739b506fa---54052675474.pdfIn PDF document text
    • http://xn--80aafmoni2biho.xn--p1ai/admin/ckfinder/userfiles/files/rizurironejawekiwasije.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=spider+far+from+home+full+movie+downloadPDF link annotation
    • 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_off0000e6c0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6C0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fed7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFED7 10824 bytes
SHA-256: f95d84ff9faabf56add95351f519f17263c976e76fee148514f6e8f54c288dc0
font_02_sfnt_off00011797.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11797 18684 bytes
SHA-256: 5cad57b814a49d24167096d7caaf1ab8dcdf8d84d77af93de3789c5567098a46