Malicious PDF — malware analysis report

Static analysis result for SHA-256 834184a4d69fe4ae…

MALICIOUS

PDF

16.7 KB First seen: 2021-10-01
MD5: dc23579b3060cba447da52e887ed5d40 SHA-1: a40379a09ace360d69ad5691b779bb00ed953ed7 SHA-256: 834184a4d69fe4ae901ec72d67d821b859c8081ea9be7b283587cd5daec6014d
120 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is a PDF file that contains a critical heuristic firing for a Type 1 Multiple-Master font overflow exploit, commonly associated with CVE-2010-1797. This indicates the file is designed to exploit a vulnerability in PDF readers to achieve code execution. ClamAV also detected it as a dropper, suggesting it likely downloads and executes additional malicious payloads.

Machine Learning

  • Nyx PDF Classifier clean score 0.0266

Heuristics 2

  • Type 1 Multiple-Master font overflow exploit (jailbreakme / CVE-2010-1797) critical CVE related PDF_TYPE1_MM_FONT_OVERFLOW
    PDF embeds a Type 1 (PostScript) font that carries Multiple Master Blend keys (BlendDesignPositions/BlendAxisTypes/BlendDesignMap) together with an over-long clear-text overflow filler (a giant repeated-token array, a 1 KB+ contiguous junk token, or a 'blatantly invalid' self-label). Multiple Master is a deprecated Type 1 sub-format whose Blend handling drives a stack buffer overflow in the FreeType / Adobe CoolType font parser — the static shape of the 2010 'jailbreakme' PDF font 0-day (CVE-2010-1797), the /FontFile (Type 1) counterpart to the CVE-2010-2883 SING exploit. The malicious bytes live inside a FlateDecoded /FontFile, so JS, heap-spray and raw-byte rules never see them; rendering one glyph in the font forces the vulnerable parse.
  • ClamAV: Pdf.Dropper.Agent-7387411-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Dropper.Agent-7387411-0

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_000_off000003eb.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x3EB 414921 bytes
SHA-256: c8d75f30ae53f687b9171a34f6f58107bf60907da2a69e134d69f2857b102b94