Malicious PDF — malware analysis report

Static analysis result for SHA-256 257b7c1bfcf3947b…

MALICIOUS

PDF

86.2 KB Created: 2021-08-26 11:43:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: ddba10fd4f7e35285575596600586640 SHA-1: 0ed6f333dc3492a0aa549f1e4cbf9d9856d02d53 SHA-256: 257b7c1bfcf3947b236b6d9fa50fa66983afdb39ee968b6d7d10ac92490fc24d
156 Risk Score

Malware Insights

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

The PDF contains a link farm directing to multiple URLs, many of which are hosted on compromised WordPress upload directories or disposable domains. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The embedded URLs suggest a tactic of using link farms to obscure the final malicious destination.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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://zzhqhi.com/d/files/didasag.pdf
    • https://plumcourse.com/wp-content/plugins/super-forms/uploads/php/files/34a0702d77600fc87eeae3f9c41304dd/muwulojaranut.pdf
    • http://primebrokeragetx.com/ckfinder/userfiles/files/65224082621.pdf
    • https://voyagerf.ru/wp-content/plugins/super-forms/uploads/php/files/7c84c19957703f96014b53e9bf8a37b8/53192074903.pdf
    • http://www.pzkexie.com/up_files/file/wamopakobuzasomep.pdf
    • http://northcity.rs/slike/files/xosabojexomonesox.pdf
    • http://bagliodeimille.it/userfiles/files/81515402723.pdf
    • https://law.com.sg/wp-content/plugins/super-forms/uploads/php/files/a3d17250805d07b2de1af0afb51b37e5/84779863288.pdf
    • https://www.ideakliniksisli.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609bf06e7cbde---nafisabisevalonupomiwanup.pdf
    • http://bacviettech.vn/userfiles/file/17665310714.pdf
    • https://cakenflowersonline.com/userfiles/file/65925528416.pdf
    • https://accesoriosalmayor.com/images/userfiles/file/71854015885.pdf
    • http://thegreenlegacykeepers.com/clients/e/e8/e8dc17949b7ef813e9937e453902477f/File/gamexiwizisaxewusabalox.pdf
    • http://anhuishangbiao.com/upload_fck/file/2021-4-29/20210429042611621742.pdf
    • https://www.heracles-hotel.eu/wp-content/plugins/super-forms/uploads/php/files/ncn8e1e8hu1tqcr3m2lgtenfe6/77264929432.pdf
    • http://sochistandart.com/ckfinder/userfiles/files/84632056068.pdf
    • http://www.kidnuri.com/wp-content/plugins/formcraft/file-upload/server/content/files/16084175f8f9f0---19992173717.pdf
    • http://ogledalata.bg/uploads/pages/files/21709786624.pdf
    • http://starwindows.ie/ckfinder/userfiles/files/kasurefipikelixizi.pdf
    • http://sahamit.net/userfiles/file/9300660534.pdf
    • https://www.ciabrini-immobilier.com/wp-content/plugins/super-forms/uploads/php/files/sqvdfrn787c96s69j2pnucek3t/88451222479.pdf
    • https://samuelben-horin.com/userfiles/file/pelopexowenutuzaw.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=referencing+a+website+without+an+author
    • 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_off0000ec35.bin
1407996cf75c6b13538f824222956e3910ca955c85cf37e9f3e46bc87f6bacaf
pdf-font-stream PDF embedded font (sfnt) at offset 0xEC35 17316 bytes
font_01_sfnt_off0001196f.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1196F 16792 bytes
font_02_sfnt_off00013186.bin
9913c593c5ab23bb2fca5a25bfc9471aac2c1a41d190743bed4db7055ecf0eeb
pdf-font-stream PDF embedded font (sfnt) at offset 0x13186 10940 bytes