Malicious PDF — malware analysis report

Static analysis result for SHA-256 51cab795c9aa77f8…

MALICIOUS

PDF

70.6 KB Created: 2021-09-07 15:13:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 1792dd58d3605e4af10fbd512a128543 SHA-1: 67c8bebf5815001ad4c3e97d4358f991050b7b6a SHA-256: 51cab795c9aa77f8ac2b43f73010f9ed95ecb8c57a0f48140e5e4b0b260ec288
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs pointing to compromised WordPress sites and other disposable hosting, indicative of a link farm used for phishing or malware distribution. The ML classifier and ClamAV detection strongly suggest malicious intent. While no scripts were directly extracted, the PDF structure and embedded URIs are consistent with techniques used to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9916

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://medvor.ru/uplcv?utm_term=mock+test+ielts+pdf
    • http://aibasylhet.edu.bd/app/webroot/ckfinder/userfiles/files/gusut.pdf
    • https://eliteplacementagency.com/uploads/files/93712070402.pdf
    • https://takiminsahada.com/wp-content/plugins/super-forms/uploads/php/files/gisb34j8vmnb6c5mb6d44fdod9/67376319718.pdf
    • https://xn--64-mlcufjjaii0l.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/be3df1eb44ac36707f9a87bae57baa8f/zugewapodotokeg.pdf
    • https://unicornproduction.gr/wp-content/plugins/super-forms/uploads/php/files/e2fb0d2c23877c00c537a67f0bf5c5c9/47862756151.pdf
    • https://12shio3.com/contents/files/95975665119.pdf
    • http://www.fliesen-brill.de/wp-content/plugins/formcraft/file-upload/server/content/files/1608ddcaab0319---89552804174.pdf
    • http://www.ponderosafestival.com/wp-content/plugins/formcraft/file-upload/server/content/files/16113a3960b710---konewuviretasafub.pdf
    • http://ilovechardonnayhills.com/userimages/93717336655.pdf
    • http://writtenmail.com/upload_images/file/93960991708.pdf
    • https://kotata-zlin.cz/obr/clanky/file/wamujajozekaberejagisa.pdf
    • https://tanthuantelecom.com/upload/fck/file/89633788532.pdf
    • https://harrisitalia.it/uploads/file/96388769151.pdf
    • https://bakwanudang.com/contents//files/88818884333.pdf
    • https://amoslodge10.org/ckfinder/userfiles/files/24517373435.pdf
    • http://concept-art.nl/app/webroot/files/userfiles/files/99635571815.pdf
    • http://www.asap-recruitment.net/upload/file/36992496790.pdf
    • http://bsbcarpet.com/userfiles/file/zodew.pdf
    • https://graffitipaintstudio.com/wp-content/plugins/super-forms/uploads/php/files/d9968f43da8bc4accdfc7d4ccc1b19b8/66746304506.pdf
    • https://bodzlomu.com/userfiles/file/40994921798.pdf
    • http://jockmurray.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607ba1b43f055---rikugepogapo.pdf
    • https://merydian.pl/nowymerydian/userfiles/file/vamekofarikotunozem.pdf
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/160e530b1bfe84---bulebixedewa.pdf
    • https://artasedanasingaraja.com/uploadfck/file/lulaba.pdf
    • http://ideviceplus.be/app/webroot/files/userfiles/files/wigubobemobufonezipabuzuf.pdf
    • http://amdind.com/userfiles/file/gojavefa.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b8a5.bin
f8d8cf5ab4653977930fb61c9e647a68448e95e0cb32a8cab28461a4dfa936be
pdf-font-stream PDF embedded font (sfnt) at offset 0xB8A5 10332 bytes
font_01_sfnt_off0000d01b.bin
a489ce1e569ae67be4ec3c36c291ed77aad1fd305f1a47a90296a6548c563dc1
pdf-font-stream PDF embedded font (sfnt) at offset 0xD01B 14632 bytes
font_02_sfnt_off0000f4a8.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF4A8 16792 bytes