Malicious PDF — malware analysis report

Static analysis result for SHA-256 1f67879fc1b501cb…

MALICIOUS

PDF

87.5 KB Created: 2021-09-09 19:00:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 90c66bea2e9d29bed7a50f9b695d7df0 SHA-1: 7bd31abaa6378cdf859e17906e3d2d344d43fba4 SHA-256: 1f67879fc1b501cb3a56b59818e68c475910361a26aa798389bd3a9f4007875c
156 Risk Score

Malware Insights

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

The file was identified as malicious by ML classifiers and ClamAV, flagging it as a phishing trojan. Static analysis revealed it functions as a link farm, with numerous embedded URLs pointing to other PDF files hosted on various domains. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a pattern of using disposable hosting for link aggregation, often associated with SEO abuse or distributing malicious content. The presence of multiple external URIs and link farm characteristics suggests an attempt to redirect users to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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 http://wonderful-foods.net/userfiles/file/20046265860.pdf
    • http://electriccityusa.com/images/fck_uploads/file/basefe.pdf
    • http://brlairport.com/images/file/leguvedinarezefozaf.pdf
    • https://verticala.ro/images/userfiles/netisanamozi.pdf
    • http://viorina-deko.com/images/file/soranevujupeb.pdf
    • http://thanhcongtechtra.com/upload/files/zafuzepexa.pdf
    • http://gcsiva.com/files/userfiles/file/23521125282.pdf
    • http://pijntherapie.be/uploads/files/vujavabuv.pdf
    • http://pietroquatriniarchitetto.eu/userfiles/files/52214653908.pdf
    • http://www.udelimpa.es/ckfinder/userfiles/files/32814852816.pdf
    • http://kutscher-customs.de/gfx/userfiles/files/33003427132.pdf
    • https://www.champagne-auge-dascier.com/ckfinder/userfiles/files/nevanowi.pdf
    • https://ateneoarbonaida.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139302d62418---28359090190.pdf
    • http://dr-onesrl.com/userfiles/files/96704495923.pdf
    • http://3sdent.com/upload/files/40603930782.pdf
    • http://wtmongolia.com/materials/file/xilenebofokubuzafadi.pdf
    • http://boathousebrokerage.com/userfiles/file/1497593352.pdf
    • http://www.elsecretodelolivo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612ec46ed10c0---94126792384.pdf
    • http://kedehg.com/ckfinder/userfiles/files/99178104334.pdf
    • https://creativenursery.net/home/creative/public_html/ckfinder/userfiles/files/46739538078.pdf
    • http://nscenter.cn/upload/files/99294108605.pdf
    • http://jurabos.nl/include/editor/file/32151754701.pdf
    • http://valencia.thepokeluau.com/uploads/files/60071400741.pdf
    • http://bangtutrang.com/upload/files/joponofemiribawana.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=outlook+search+repair+utility+mac
    • https://bxthirteen.wpengine.com/wp-content/plugins/super-forms/uploads/php/files/c60b453fb744e4b4e23404315972884b/22378868369.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_off0000ede3.bin
556f81b39cde610316ec60906df840648beafb442bb8400e88b66200c199fa33
pdf-font-stream PDF embedded font (sfnt) at offset 0xEDE3 18996 bytes
font_01_sfnt_off00011f4c.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x11F4C 16792 bytes
font_02_sfnt_off00013763.bin
73185949648da6191125d74ffce1f816dcb6361f38c1d50c167da32d4370c3ca
pdf-font-stream PDF embedded font (sfnt) at offset 0x13763 10868 bytes